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Author: Palma Scarcia

Pol Sallés Perramon

Written by Palma Scarcia on . Posted in Postdoctoral.

I obtained my Bachelor’s degree in Nanoscience and Nanotechnology and later completed the Erasmus Mundus Master in Materials for Energy Storage and Conversion (MESC). I earned my PhD in Materials Science at ICMAB-CSIC in 2023, under the supervision of Dr. Mariona Coll, with a  “La Caixa” INPhINIT fellowship (Marie Curie) and awarded with the CSIC Relevant Doctoral Thesis. After my PhD, I joined the European Synchrotron Radiation Facility (ESRF) in Grenoble as a postdoctoral scientist at beamline ID31, where I worked until 2025 before coming back to ICMAB a postdoctoral scientist.

My research expertise lies in the synthesis and characterization of functional oxide thin films and membranes prepared by chemical methods, and in the study of their structural evolution under external stimuli. During my PhD, I focused on developing single-crystalline freestanding complex oxide membranes using cost-efficient chemical routes, while at ESRF I applied advanced synchrotron-based X-ray diffraction techniques to investigate operando structural transformations in MXenes and oxide membranes for energy applications.

Here at ICMAB, I carry out my research together with Dr. Mariona Coll, focusing on the use of freestanding oxide membranes for energy applications, particularly on how strain influences their physical properties. I combine this research with teaching duties as an Assistant Professor at UPC.

Roger Guzman

Written by Palma Scarcia on . Posted in Permanent Researchers.

I am a CSIC Tenured Scientist at ICMAB since 2024. I received my PhD in Materials Science and Technology in 2014 from Universitat Autònoma de Barcelona. After graduation, I continued my research activity as a post-doc researcher in different national laboratories (Insituto de Nanociencia de Aragón, INA, 2014; Universidad Complutense de Madrid, UCM, 2015; Institut de Ciència de Materials de Barcelona, ICMAB, 2016) becoming an expert in the field of aberration-corrected scanning transmission electron microscopy applied to complex oxides. 

From 2019 to 2024, I was part of the STEM group at the University of Chinese Academy of Science, UCAS (Beijing, China), first as a post-doc and later as a permanent research scientist. 

Research interest

My research focuses on the development and implementation of advanced scanning transmission electron microscopy (STEM) analytical tools for the characterization of nanomaterials and low-dimensional systems. In particular, I employ four-dimensional STEM and vibrational electron energy-loss spectroscopy (EELS) to investigate novel superconducting oxide interfaces and twisted bilayer oxide membranes.

My broader goal is to establish a synergistic research program that combines microscopy, materials science, and condensed matter physics at the frontier of analytical electron spectroscopy. I aim to elucidate the relationships between structure, chemistry, and physical properties in low-dimensional systems—such as heterostructures, interfaces, and defects—down to the single-atom level.

Master Thesis

Written by Palma Scarcia on . Posted in FEATURED, News.

Sara Sales Merino, student in the degree of Physics (UAB) is developing an internship (JAE INTRO) under supervision of Gervasi Herranz on the project of manybody theory of strongly correlated systems.

Stoichiometric control of electron mobility

Stoichiometric control of electron mobility and 2D superconductivity at LaAlO3-SrTiO3 interfaces

Written by Palma Scarcia on . Posted in FEATURED, News.

ISrTiO3-based conducting interfaces, which exhibit coexistence of gate-tunable 2D superconductivity and strong Rashba spin-orbit coupling (RSOC), are candidates to host topological superconductive phases. Yet, superconductivity is usually in the dirty limit, which tends to suppress nonconventional pairing and therefore challenges these expectations. Here we report on LaAlO3/SrTiO3 (LAO/STO) interfaces with large mobility and mean free paths comparable to the superconducting coherence length, approaching the clean limit for superconductivity. We further show that the carrier density, mobility, and formation of the superconducting condensate are controlled by the fine-tuning of La/Al chemical ratio in the LAO film. We find a region in the superconducting phase diagram where the critical temperature is not suppressed below the Lifshitz transition, at odds with previous experimental investigations. These findings point out the relevance of achieving a clean-limit regime to enhance the observation of unconventional pairing mechanisms in these systems.

Janine Gückelhorn delivers a talk at APS March Meeting 2025

Written by Palma Scarcia on . Posted in FEATURED, News.

Janine Gücklehorn delivers a talk at APS March Meeting 2025 (Anaheim, California). The title of the talk is “Effect of dielectric polarizability on Rashba spin-orbit coupling in Al/Sr1-xCaxTiO3 interfaces” in the Session MAR-W52 “Emerging Trends in Perovskite Oxides: Structure, Properties, and Applications” 

Friday March 21 10:00 am

Giant spin-charge conversion in ultrathin films of the MnPtSb half-Heusler compound

Written by Palma Scarcia on . Posted in FEATURED, News.

E. Longo et al. Giant Spin-Charge Conversion in Ultrathin Films of the MnPtSb Half-Heusler Compound. Advanced Functional Materials 2407968 (2024)

DOI: https://doi.org/10.1002/adfm.202407968

Abstract:

Half-metallic half-Heusler compounds with strong spin-orbit-coupling and broken inversion symmetry in their crystal structure are promising materials for generating and absorbing spin-currents, thus enabling the electric manipulation of magnetization in energy-efficient spintronic devices. In this work, we report the spin-to-charge conversion in the sputtered half-Heusler MnPtSb within thickness (t) range from 1 to 6 nm. A combination of X-ray and transmission electron microscopy measurements evidence the epitaxial nature of these ultrathin non-centrosymmetric layers, with a clear (111)-orientation on top of (0001) single-crystal sapphire. By broadband ferromagnetic resonance (FMR), we observe a four orders of magnitude tunable spin accumulation in the MnPtSb-based heterostructures, within t=1-6 nm range. By using spin pumping FMR, we measure a remarkable t-dependent spin-charge conversion in the MnPtSb layers, which clearly demonstrates the interfacial origin of the conversion. When interpreted within the inverse Edelstein effect (IEE), the spin-charge conversion efficiency extracted at room temperature for the thinnest MnPtSb layer reaches λIEE~3 nm, representing an extremely high conversion at room temperature. The still never explored ultrathin regime of the MnPtSb films studied in this work and the discovery of their outstanding functionality are two ingredients which demonstrate the potentiality of such materials for future applications in spintronics. 

Prof. Kyle Shen deliveres a talk at ICMAB entitled “Thin Film Nickelates: A New Frontier for High-Temperature Superconductivity”

Written by Palma Scarcia on . Posted in FEATURED, News.

Prof. Kyle Shen, from the Department of Physics at Cornell University, deliveres a talk at ICMAB entitled “Thin Film Nickelates: A New Frontier for High-Temperature Superconductivity”.

Here the abstract about the talk:

Superconductivity plays a key role in many next-generation technologies, including quantum computing and sensing. The promise of discovering new superconductors with higher transition temperatures has been at the forefront of research in condensed matter physics, materials science, and solid state chemistry for the past 4 decades. From the high-temperature cuprate superconductors of the 1990s, to the iron-based superconductors of the 2010s, significant attention has now been directed in the past few years to the nickelate families of superconductors, particularly the so-called “infinite layer” nickelates as well as the recently discovered bilayer nickelate, La3Ni2O7.

In this seminar, I will describe recent advances in the study of the infinite-layer and bilayer nickelate superconductors. I will highlight new thin film synthesis approaches developed by our research group, and how this enables investigations of superconductivity and the phase diagram of both these families.

PhD Student Mario Villa delivered two oral presentations at the EMRS 2024 Spring meeting in held in Strasbourg last May.

Written by Palma Scarcia on . Posted in FEATURED, News.

MULFOX’ PhD Student Mario Villa contributed with two oral presentations entitled “Large photoresponse and grain boundaries of LaFeO3-based heterojunctions” and “Microstructural domain mapping of LaFeO3-based heterojunctions” within the Advanced PV material characterization and Analytical techniques for accurate nanoscale characterization of advanced materials symposiums respectively during the EMRS Spring meeting held in Strasbourg, France during May, 2024. 

Unfolding the Challenges To Prepare Single Crystalline Complex Oxide Membranes by Solution Processing

Written by Palma Scarcia on . Posted in FEATURED, News.

Pol Salles, Roger Guzman, Huan Tan, Martí Ramis, Ignasi Fina, Pamela Machado, Florencio Sánchez, Gabriele De Luca, Wu Zhou, and Mariona Coll

ACS Appl. Mater. Interfaces 2024 (2024)

DOI: https://doi.org/10.1021/acsami.4c05013

Abstract

The ability to prepare single crystalline complex oxide freestanding membranes has opened a new playground to access new phases and functionalities not available when they are epitaxially bound to the substrates. The water-soluble Sr3Al2O6 (SAO) sacrificial layer approach has proven to be one of the most promising pathways to prepare a wide variety of single crystalline complex oxide membranes, typically by high vacuum deposition techniques. Here, we present solution processing, also named chemical solution deposition (CSD), as a cost-effective alternative deposition technique to prepare freestanding membranes identifying the main processing challenges and how to overcome them. In particular, we compare three different strategies based on interface and cation engineering to prepare CSD (00l)-oriented BiFeO3 (BFO) membranes. First, BFO is deposited directly on SAO but forms a nanocomposite of Sr–Al–O rich nanoparticles embedded in an epitaxial BFO matrix because the Sr–O bonds react with the solvents of the BFO precursor solution. Second, the incorporation of a pulsed laser deposited La0.7Sr0.3MnO3 (LSMO) buffer layer on SAO prior to the BFO deposition prevents the massive interface reaction and subsequent formation of a nanocomposite but migration of cations from the upper layers to SAO occurs, making the sacrificial layer insoluble in water and withholding the membrane release. Finally, in the third scenario, a combination of LSMO with a more robust sacrificial layer composition, SrCa2Al2O6 (SC2AO), offers an ideal building block to obtain (001)-oriented BFO/LSMO bilayer membranes with a high-quality interface that can be successfully transferred to both flexible and rigid host substrates. Ferroelectric fingerprints are identified in the BFO film prior and after membrane release. These results show the feasibility to use CSD as alternative deposition technique to prepare single crystalline complex oxide membranes widening the range of available phases and functionalities for next-generation electronic devices.

Invited Talks by Gyanendra Singh and Gervasi Herranz at the 7th International Workshop on Complex Oxides, Cargèse, Corsica

Written by Palma Scarcia on . Posted in FEATURED, News.

We are pleased to announce that Gyanendra Singh and Gervasi Herranz will be delivering invited talks at the 7th International Workshop on Complex Oxides in Cargèse, Corsica. Gyanendra Singh will discuss “Stoichiometric Control of 2D Superconductivity and Mobility at SrTiO3-Based Interfaces,” while Gervasi Herranz will present on “Spin-Orbit Entanglement Driven by the Jahn-Teller Effect.” Join us for these insightful sessions on groundbreaking research in complex oxides!

Teodor Apetrei

Written by Palma Scarcia on . Posted in PhD students.

Teodor Apetrei started his PhD studies at ICMAB-CSIC, participating in the MUST project, in November 2023. He earned his BSc in Computational Physics from Alexandru Ioan Cuza University in Iasi, Romania, in 2020, and his MSc in Applied and Engineering Physics from the Technical University of Munich, Germany, in 2023. His research primarily involves the growth and engineering of magnetic oxide and nitride thin films using magnetron sputtering with tunable interfacial chiralic magnetism and perpendicular anisotropy.

Weronika Janus

Written by Palma Scarcia on . Posted in Postdoctoral.

Weronika Janus began her role as a Postdoctoral researcher at ICMAB-CSIC, working on the SMARTSPIN project, in November 2023. She completed her BSc in Biomedical Engineering in 2018 and her MSc in Biomedical Engineering with a focus on Bionanotechnology in 2019, both at AGH University of Krakow, Poland. She then started her PhD in Physics at the same institution in 2019, concentrating on manipulating the magnetic properties of antiferromagnetic thin films through strain. Her current research interest is in developing innovative magnetic insulator-based spintronic memory devices, where the information can be written and read by all-electrical means

Takayuki Shiino

Written by Palma Scarcia on . Posted in Postdoctoral.

Takayuki Shiino became a postdoctoral researcher at ICMAB-CSIC, contributing to the MAGNEPIC project in March 2024. He earned a Bachelor’s degree in Physics from Tokyo Institute of Technology in 2013, followed by a Master’s degree in Materials Science and Engineering from KAIST in 2016. In 2019, he completed his Ph.D. at Nagoya University with a dissertation on quantum critical phenomena in heavy-fermion materials. Post-PhD, he held two postdoctoral positions: at Uppsala University (2019 – 2021, Sweden) researching quasicrystals, and at KAIST (2022 – 2024, South Korea) focusing on spintronics. His current research involves spintronic devices utilizing insulating ferrimagnetic materials.

The 3rd ICMAB School on Berry and Rashba Physics in Quantum Confined Systems 2024 has concluded

Written by Palma Scarcia on . Posted in FEATURED, News.

The School was held on 30 and 31 May 2024, and had a participation of 150 attendants, among them 36 in-person and 114 online.

The school included a seminar on “Signatures of a spin-orbital chiral metal” by Mario Cuoco on 29th May. It was followed by lectures on 30th and 31th May by Annika Johansson, Andrea Caviglia and Mario Cuoco, which motivated lively discussions, comments and suggested intriguing prospectives.

The chemistry of functional oxides

Written by Palma Scarcia on . Posted in Research Areas.

RESEARCH AREAS

The chemistry of functional oxides

Transition metal complex oxides are a rich family of compounds presenting extraordinary physical phenomena ranging from superconductivity, multiferroicity, magnetism, catalytic activity to simultaneous optical transparency and electric conductivity holding great potential to outperform conventional semiconductors for many electronic and energy applications. Their properties are highly sensitive to several parameters including their structure, composition, stoichiometry, crystalline orientation, strain and dimension. Achieving sufficiently precise control of these parameters and therefore on their properties requires an accurate synthesis procedure. 

Chemical deposition procedures are gaining attention as versatile and eco-friendly approaches to develop engineered functional complex oxides by properly selecting compatible chemical precursors and designing an specific thermal treatment. The conversion process that the chemical precursors undergoes to form the desired oxides completely differs to that described for physical deposition techniques offering unique opportunities to synthesize complex oxides with distinct properties.

We explore the frontiers of chemical procedures to design complex oxides in the form of thin films, nanostructures, heterostructures and freestanding membranes prioritizing the use of low-toxic and abundant elements. The focus is placed on understanding the chemistry-structure-property relationship to be able to design innovative materials with tailored properties for next-generation electronic devices.

Researchers

  • Mariona Coll

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Martí Ramis

Written by Palma Scarcia on . Posted in PhD students.

Martí Ramis obtained a Bachelor degree in Chemistry at Universitat de Barcelona and  a Master degree in Advanced Nanoscience and Nanotechnology at Universitat Autònoma de Barcelona. He joined Dr. Mariona Coll team as FPI PhD student in December 2022. The topic of his research is on the development of flexible complex oxide membranes via cost-effective chemical methods and to explore the unique properties that these unconventional structures can offer for energy and electronic applications.

Mariona Coll

Written by Palma Scarcia on . Posted in Permanent Researchers.

My research expertise ranges across the cost-effective synthesis of oxides and their chemical and structural characterization to develop functional materials with tailored properties focusing on electronic and energy harvesting applications.

Currently, my research interests are on the rational design of chemical procedures to prepare thin films and nanocomposites combining solution processing and atomic layer deposition. We are also interested in exploring single crystalline freestanding oxide membranes to unlock novel and enhanced properties arising from extreme flexural deformation and artificial stacking. We aim to understand the synthesis-property relationship of all these systems with special emphasis on multifunctional complex oxides including multiferroics which are attractive candidates for applications in information storage, spintronics, sensors, actuators and optoelectronics. 

I graduated in Chemistry from Universitat de Barcelona and hold a PhD in Materials Science from Universitat Autònoma de Barcelona.  I was a postdoctoral researcher at the University of Maryland and NIST (USA) for 3 years and since 2018 I am a tenured scientist at ICMAB-CSIC. I was awarded with “L’Oreal Women in Science 2017” and “Beca Leonardo FBBVA 2020”. I have given more than 30 invited talks and co-organized 6 international conferences, symposiums and schools in the field of oxides and materials for energy and electronics. I am active in the supervision of PhD students and mentoring postdocs.

ORCID: 0000-0001-5157-7764

Longyi Fan

Written by Palma Scarcia on . Posted in PhD students.

My name is Longyi Fan, from China. I finished my Master degree on Materials Science and Engineering at Dalian Jiaotong University. I joined the lab in October 2023 with a China Scholarship Council fellowship to start my PhD Thesis on the preparation and characterization of stacked single crystalline complex oxide membranes for next-generation electronic devices under the supervision of Dr. Mariona Coll. 

Karla Mena

Written by Palma Scarcia on . Posted in PhD students.

I am a DOCFAM-MSCA PhD student who joined ICMAB in June 2023 to work on Multiferroic nanocomposites for light and magnetic energy harvesting, under the supervision of Dr. Mariona Coll and Dr. Anna Palau. I obtained a Bachelor degree in Chemistry at the University of Costa Rica and a Master degree in Applied Chemistry at Chiba University, Japan. 

Mariona Coll and her team members participated at the EMRS Spring meeting 2024

Written by Palma Scarcia on . Posted in FEATURED, News.

Karla Mena, Martí Ramis, Mariona Coll and former member of the team Pol Sallés participated at the EMRS Spring meeting held in Strasburg May 2024
Karla Mena presented an oral contribution on multiferroic composites for energy harvesting, Martí Ramis presented a poster on nanomechanical properties of manganite membranes on plastic substrates, Mariona Coll delivered an invited talk on the opportunities of chemical methods to prepare freestanding complex oxide membranes and Pol Sallés presented an invited talk on the challenges to prepare BiFeO3 membranes by chemical solution deposition.

We welcome Takayuki, Weronika, and Teodor in MULFOX to work on spintronics materials and devices

Written by Palma Scarcia on . Posted in FEATURED, News.

Dr. Takayuki Shiino and Dr. Weronika Janus joined MULFOX as postdoctoral researchers, and Teodor Apetrei joined as a Ph.D. candidate. We warmly welcome them to the group and wish them success.

Takayuki received his BSc in Physics (2013) and MSc in Materials Science and Engineering (2016) from Tokyo Institute of Technology (Japan) and KAIST (South Korea), respectively. He received his Ph.D. from Nagoya University (Japan) in 2019 with a thesis on a quantum critical phenomenon in heavy-fermion materials. After the PhD, he experienced two postdoctoral researches: Uppsala University (2019 – 2021, Sweden) and KAIST (2022 – 2024, South Korea) for the studies of quasicrystals and spintronics, respectively. His postdoctoral research at MULFOX focuses on spintronic devices with insulating ferrimagnetic materials.

Weronika studied at AGH University of Krakow, Poland, where she obtained her BSc in Biomedical Engineering (2018), MSc in Biomedical Engineering – Bionanotechnology (2019), and PhD in Physics (2014). During her PhD, she focused on the strain manipulation of magnetic properties in antiferromagnetic thin films. Her current research interest is in developing innovative magnetic insulator-based spintronic memory devices, where the information can be written and read by all-electrical means

Teodor obtained his BSc. degree in Computational Physics at University Alexandru Ioan Cuza Iasi (Romania, 2020) and his MSc. degree in Applied and Engineering Physics at Technische Universitat Munchen (Germany, 2023). The main focus of his current research is the growth and engineering of magnetic oxide and nitride thin films by magnetron sputtering with tunable interfacial chiral magnetism and perpendicular anisotropy.

We organize an international School on Topological Interfaces, 30-31 May 2024, ICMAB-CSIC Barcelona

Written by Palma Scarcia on . Posted in FEATURED, News.

This is the 3rd Edition of “ICMAB Schools on Frontiers in Materials Science and Condensed Matter”. Previous editions were “Angle Resolved Photoemission Spectroscopy (https://arpes2023.icmab.es/)” and “Orbital currents in solids (https://orbitalcurrents2023.icmab.es/)”

More information at https://topologicalinterfaces2024.icmab.es/

2024

Written by Palma Scarcia on . Posted in Publications.

Giant spin-charge conversion in ultrathin films of the MnPtSb half-Heusler compound
E. Longo, A. Markou, C. Felser, M. Belli, A. Serafini, P. Targa, D. Codegoni, M. Fanciulli, R. Mantovan Advanced Functional Materials 2407968 (2024)

Stoichiometric control of electron mobility and 2D superconductivity at LaAlO3-SrTiO3 interfaces
G. Singh, R. Guzman, G. Saïz, W. Zhou, J. Gazquez, F. Masoudinia, D. Winkler, T. Claeson, J. Fraxedas, N. Bergeal, G. Herranz & A. Kalaboukhov 
Communications Physics (2024)

Absence of 3a0 charge density wave order in the infinite-layer nickelate NdNiO2
C. T. Parzyck, N. K. Gupta, Y. Wu, V. Anil, L. Bhatt, M. Bouliane, R. Gong, B. Z. Gregory, A. Luo, R. Sutarto, F. He, Y.-D. Chuang, T. Zhou, G. Herranz, L. F. Kourkoutis, A. Singer, D. G. Schlom, D. G. Hawthorn, and K. M. Shen
Nat. Mater. (2024)

Unfolding the Challenges To Prepare Single Crystalline Complex Oxide Membranes by Solution Processinge order in the infinite-layer nickelate NdNiO2
Pol Salles, Roger Guzman, Huan Tan, Martí Ramis, Ignasi Fina, Pamela Machado, Florencio Sánchez, Gabriele De Luca, Wu Zhou, and Mariona Coll
ACS Appl. Mater. Interfaces 2024

2024

Written by Palma Scarcia on . Posted in Conferences.

REGULAR TALKS

Electromagnetic detection of spin-orbit entangled states in Jahn-Teller Mn3+ ions*
Gervasi Herranz
APS March Meeting 2024
Minneapolis, Minnesota, USA, 2024

Stoichiometric control of 2D superconductivity and mobility at SrTiO3-based interfaces
Gyanendra Singh
APS March Meeting 2024
Minneapolis, Minnesota, USA, 2024

Large photoresponse and grain boundaries of LaFeO3-based heterojunctions
Mario Villa
EMRS Spring meeting
Strasbourg, France, 2024

Microstructural domain mapping of LaFeO3-based heterojunctions
Mario Villa
EMRS Spring meeting
Strasbourg, France, 2024

Gervasi Herranz and Gyanendra Singh participate in the APS March Meeting 2024

Written by Palma Scarcia on . Posted in FEATURED, News.

Gervasi Herranz delivers a talk (IN-PERSON MEETING) on 6th March at 2:18 PM at the APS March Meeting 2024 (Minneapolis, Minnesota, USA) in Session N04: Ordering Phenomena in Spin-Orbit Coupled Systems

Room: L100D The talk is N04.00011 : Electromagnetic detection of spin-orbit entangled states in Jahn-Teller Mn3+ ions”.
Gyanendra Singh delivers a talk (VIRTUAL MEETING) on 6th March at 12:30 PM the APS March Meeting 2024 (Minneapolis, Minnesota, USA) Abstract: HH05.00006 : Stoichiometric control of 2D superconductivity and mobility at SrTiO3-based interfaces.

Absence of 3a0 charge density wave order in the infinite-layer nickelate NdNiO2

Written by Palma Scarcia on . Posted in FEATURED, News.

C. T. Parzyck, N. K. Gupta, Y. Wu, V. Anil, L. Bhatt, M. Bouliane, R. Gong, B. Z. Gregory, A. Luo, R. Sutarto, F. He, Y.-D. Chuang, T. Zhou, G. Herranz, L. F. Kourkoutis, A. Singer, D. G. Schlom, D. G. Hawthorn & K. M. Shen

Nat. Mater. (2024)

DOI: https://doi.org/10.1038/s41563-024-01797-0

Abstract

A hallmark of many unconventional superconductors is the presence of many-body interactions that give rise to broken-symmetry states intertwined with superconductivity. Recent resonant soft X-ray scattering experiments report commensurate 3a0 charge density wave order in infinite-layer nickelates, which has important implications regarding the universal interplay between charge order and superconductivity in both cuprates and nickelates. Here we present X-ray scattering and spectroscopy measurements on a series of NdNiO2+x samples, which reveal that the signatures of charge density wave order are absent in fully reduced, single-phase NdNiO2. The 3a0 superlattice peak instead originates from a partially reduced impurity phase where excess apical oxygens form ordered rows with three-unit-cell periodicity. The absence of any observable charge density wave order in NdNiO2 highlights a crucial difference between the phase diagrams of cuprate and nickelate superconductors.

Enhanced spin current transmissivity in Pt/CoFe2O4 bilayers with thermally induced interfacial magnetic modification

Written by Palma Scarcia on . Posted in FEATURED, News.

M. Gamino, A. B. Oliveira, D. S. Maior, P. R. T. Ribeiro, F. L. A. Machado, T. J. A. Mori, M. A. Correa, F. Bohn, R. L. Rodríguez-Suárez, J. Fontcuberta, and S. M. Rezende

Phys. Rev. B 2023, 108, 224402;

DOI: https://doi.org/10.1103/PhysRevB.108.224402

Abstract

We report on processes of generation of spin current and conversion into charge current in CoFe2O4/Pt bilayers by means of spin Hall magnetoresistance (SMR) and spin Seebeck effect (SSE) experiments. Specifically, we explore (001) full-textured CoFe2O4 (CFO) thin films grown onto (001)-oriented SrTiO3 substrates, covered with Pt layers deposited under two different conditions: one at room temperature and another at high temperature (400∘C). The x-ray absorption spectroscopy measurements indicate that the Pt layer deposited at high temperature induces an interfacial magneticlike phase (Fe,Co)-Pt alloy, which influences the magnetic behavior of the structure and is responsible for the enhancement of the spin transmission at the interface. By analyzing the SMR data, we conclude that collinear and noncollinear magnetic domains coexist at the CFO-(Fe,Co)-Pt interface. By combining the data from the SMR and SSE measurements, we obtain the ratios between the values of the spin Hall angle (θSH) and between the ones of the spin-mixing conductance (g↑↓eff) in the two samples. We demonstrate that while the value of θSH decreases by one-half with the heat treatment, the value of g↑↓eff increases by more than one order of magnitude. We interpret the increase of g↑↓eff in terms of unexpected magnetic reconstructions, which produce an enhancement of the magnetic moment arisen at the interface. Since the spin-mixing conductance determines the efficiency of the spin current transmission through the interface, the spinel ferrite cobalt in contact with a normal metal with a suitable heat treatment becomes a promising material for spintronics device applications.

Emanuele Longo

Written by Palma Scarcia on . Posted in Postdoctoral.

After graduating with honors in solid state physics in 2017 from the University of Milan-Bicocca, in 2021 Dr. Longo successfully defended his doctoral thesis in the field of spintronics, earning the title of Doctor of Science and Nanotechnology of Materials at the same university, within a collaboration with the Institute of Microelectronics and Microsystem in Agrate-Brianza of the Italian national council of research (CNR-IMM). From 2021 to July 2023, he was postdoctoral research fellow at the CNR-IMM in the framework of the SKYTOP European project.  

During his PhD activity and first postdoctoral activity, Dr. Longo studied the chemical-physical interactions between an exotic phase of matter known as “topological insulator” and ferromagnetic materials, with the aim to produce efficient spintronic devices for memory storage and logic applications. In particular, he investigated the properties of topological systems when used to convert spin currents into charge currents (and vice versa). He contributed to develop an industrially compatible deposition process to produce Sb2Te3 topological insulator thin films on 4’’ silicon wafers, demonstrating their remarkable spin-to-charge current conversion efficiency.

Here at ICMAB, Dr. Longo carries out under supervision of Prof. Fontcuberta a fundamental study of the detection, and characterization of orbital currents in early transition metals metallic oxides, activity which lies in the framework of the so-called “spinorbitronics”. The possibility to use light materials and their exceptional transport properties make the orbital currents very promising to be exploited in the future micro- and nano- electronic devices.

Yinhgjie Zhu

Written by Palma Scarcia on . Posted in PhD students.

Yingjie Zhu pursues a PhD in Light-matter interactions, with the objective to explore spin-orbit entanglement in Jahn-Teller correlated systems.

Orbital Currents School 2023

Written by Palma Scarcia on . Posted in FEATURED, News.

The ICMAB organized Orbital Currents School 2023 conclued. 

With a participation of about 70 attendants in-person and 110 on line, the School has finished. A very exciting Introductory lecture by Tatiana G. Rappoport, was followed by lectures by Aurélien Manchon, Dongwook Go, Enric Canadell, Hyun-Woo Lee and Can Onur Avci, which motivated living discussions, comments and suggested intriguing prospectives.

Emanuele joins the lab as postdoc to work on “Orbital currents in early transition metals metallic oxides”

Written by Palma Scarcia on . Posted in News.

During his PhD and previous postdoc, Dr. Longo studied the chemical-physical interactions between an exotic phase of matter known as “topological insulator” and ferromagnetic materials, with the aim to produce efficient spintronic devices for memory storage and logic applications. In MULFOX, Dr .Longo studies the detection, and characterization of orbital currents in early transition metals metallic oxides, activity which lies in the framework of the so-called “spinorbitronics”. The possibility to use light materials and their exceptional transport properties make the orbital currents very promising to be exploited in the future micro- and nano- electronic devices.

Yingjie Zhu joins the lab as PhD student

Written by Palma Scarcia on . Posted in News.

Yingjie Zhu joins the lab as PhD student to work on “Spin-orbit-entangleement in Jahn-Teller Systems”. 

Yingjie Zhu, comes from China. She did her master’s research in Materials Science and Engineering. She joins the lab to pursue a PhD in Light-matter interactions, the objective is to explore spin-orbit entanglement in Jahn-Teller correlated systems. Yingjie Zhu loves Chinese poetry”

Jiahui Jia’s PhD Thesis

Written by Palma Scarcia on . Posted in News.

Jiahui Jia’s Thesis investigates ways to manipulate the structural realizations of materials with external fields, allowing for dynamic tuning of their properties. The focus is on altering lattice distortions, particularly octahedral rotations, to modify their characteristics. Attention is paid to magnetism, including antiferromagnetic order and spin canting. Using DFT, Jiahui Jia has discovered various techniques for manipulating lattice distortions and establish a comprehensive connection between these distortions and the ensuing magnetism. These findings provide a route for designing structures with adjustable magnetic properties, which can contribute to the development of sophisticated materials with tailored functionalities. 

The supervisors of this Thesis are Miguel Pruneda, from Nanomaterials and Nanotechnology Research Center (CINN-CSIC) and  Gervasi Herranz, from MULFOX, ICMAB-CSIC

Rubén García Llorente joins the lab with a JAE Intro

Written by Palma Scarcia on . Posted in News.

Rubén is currently studying a master’s degree in theoretical particle physics and cosmology at the Universitat de Barcelona. He combines his studies with an introductory research grant JAE INTRO in our group, to work in the area of Quantum transport and light-matter interactions, using manybody physics approach. He studies spin-orbit entanglement in correlated systems based on Mn3+ ions.

High-Temperature Synthesis of Ferromagnetic Eu3Ta3(O,N)9 with a Triple Perovskite Structure

Written by Palma Scarcia on . Posted in News.

Jhonatan R. Guarín, Carlos Frontera, Judith Oró-Solé, Jaume Gàzquez, Clemens Ritter, Josep Fontcuberta*, and Amparo Fuertes

Inorg. Chem. 2023, 62, 42, 17362–17370;

DOI: https://doi.org/10.1021/acs.inorgchem.3c02691

Abstract

Europium tantalum perovskite oxynitrides were prepared by a new high-temperature solid-state synthesis under N2 or N2/H2 gas. The nitrogen stoichiometry was tuned from 0.63 to 1.78 atoms per Eu or Ta atom, starting with appropriate N/O ratios in the mixture of the reactants Eu2O3, EuN and Ta3N5, or Eu2O3 and TaON, which was treated at 1200 °C for 3 h. Two phases were isolated with compositions EuTaO2.37N0.63 and Eu3Ta3O3.66N5.34, showing different crystal structures and magnetic properties.

Electron diffraction and Rietveld refinement of synchrotron radiation X-ray diffraction indicated that EuTaO2.37N0.63 is a simple perovskite with cubic Pm3̅m structure and cell parameter a = 4.02043(1) Å, whereas the new compound Eu3Ta3O3.66N5.34 is the first example of a triple perovskite oxynitride and shows space group P4/mmm with crystal parameters a = 3.99610(2), c = 11.96238(9) Å. The tripling of the c-axis in this phase is a consequence of the partial ordering of europium atoms with different charges in two A sites of the perovskite structure with relative ratio 2:1, where the formal oxidation states +3 and +2 are respectively dominant. Magnetic data provide evidence of ferromagnetic ordering developing at low temperatures in both oxynitrides, with saturation magnetization of about 6 μB and 3 μB per Eu ion for EuTaO2.37N0.63 and the triple perovskite Eu3Ta3O3.66N5.34 respectively, and corresponding Curie temperatures of about 7 and 3 K, which is in agreement with the lower proportion of Eu2+ in the latter compound.

Janine Gückelhorn joins as postdoc to research on two-dimensional electron gases at quantum paraelectric interfaces

Written by Palma Scarcia on . Posted in News.

Janine Gückelhorn has developed his Ph.D at the Walther-Meissner-Institute, Bavarian Academy of Sciences and Humanities in Germany. Her research is focused on Magnetism and Spintronics and, in particular, Spin Currents and Magnon Transport. He works at ICMAB on two-dimensional electron gases on quantum paraelectric interfaces.

Talk “Spin-orbit mixing in Mn3+ driven by Jahn-Teller and spin-orbit interactions” at the International Workshop on Oxide Electronics WOE29, Busan, South Korea, 18th October 2023

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Gervasi Herranz has delivered a talk on “Spin-orbit mixing in Mn3+ driven by Jahn-Teller and spin-orbit interactions ” at the 29th International Workshop on Oxide Electrons, Busan, Republic of Korea. In the talk, Gervasi Herranz explained the latest results on our research on spin-orbit entangled states in Mn3+ systems, using electromagnetic fields to probe and manipulate these states.

Electrical characterization and extraction of activation energies of the defect states in the LaAlO3/SrTiO3 heterostructure

Written by Palma Scarcia on . Posted in FEATURED, News.

Yoann Lechaux, Yu Chen; Albert Minj, Florencio Sánchez, Gervasi Herranz, Laurence Méchin, Bruno Guillet

Appl. Phys. Lett. 121, 081904 (2022); DOI: https://doi.org/10.1063/5.0101255

 

Abstract

In this work, we study the electronic properties of defects in the LaAlO3/SrTiO3 heterostructure, which is known to host a high mobility two-dimensional electron gas (2DEG) at the interface. This 2DEG also shows photoconductance, which could be related to defects that act as deep center trapping and releasing carriers by interaction with light. This phenomenon has raised an interest for the identification of deep energy levels in the LaAlO3/SrTiO3 heterostructure. We have studied the defect state properties using electrical characterization such as capacitance–voltage (C–V), current–voltage (I–V) measurements, and deep-level transient Fourier spectroscopy (DLTFS). From C–V and I–V analyses, a hysteresis was observed indicating an effect of mobile charges in the LaAlO3. Using DLTFS, we identify three defect states located at around 0.17 eV below conduction band and at 0.23 and 0.26 eV above the valence band. These defect states were attributed to defects in SrTiO3 such as strontium vacancies or titanium vacancies. We identify a fourth defect state having an energy of about 0.69 eV below the conduction band that could be related to oxygen vacancies in LaAlO3 or in SrTiO3. In addition, the observation of an effect of the electric field with DLTFS indicated that oxygen vacancies might be involved in Fowler–Nordheim or trap-assisted tunneling through the LaAlO3 layer.