Author: Palma Scarcia

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.

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)

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

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

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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

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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

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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

Written by Palma Scarcia on . Posted in News.

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.

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