TODAY 27 Nov. 12 pm: ICMAB Periodical Lectures “Electric-field control of magnetism in multiferroic heterostructures” By Sebastiaan van Dijken, NanoSpin, Dep. of Applied Physics, Aalto University School of Science, Finland. Sala d’Actes Carles Miravitlles
Spintronic devices currently rely on magnetic switching or controlled motion of magnetic domain walls by an external magnetic field or electric current. Achieving the same degree of magnetic controllability using an electric field has potential advantages including low power consumption. Here, an approach to electrically control local magnetic properties will be discussed [1-5]. The method is based on recurrent strain transfer from regular ferroelastic stripe domains in a ferroelectric BaTiO3 substrate to magnetostrictive films (e.g. CoFe, CoFeB, and Fe). Dominance of the strain-induced magnetoelastic anisotropy in these heterostructures causes full imprinting of ferroelectric domain patterns into ferromagnetic films and strong pinning of magnetic domain walls onto ferroelectric boundaries [6,7]. Optical polarization microscopy measurements of the ferromagnetic and ferroelectric domain structures indicate that domain correlations and strong inter-ferroic domain wall pinning are maintained in an applied electric field. As a result, deterministic electric-field control over the formation and erasure of ferromagnetic domains [1-3] and reversible motion of magnetic domain walls [4,5] are obtained. In addition, regular modulations of magnetic anisotropy in strain-coupled multiferroic heterostructures provide a versatile platform for the excitation and manipulation of spin waves [8,9]. These findings open up new routes towards electric-field driven spintronics and magnonics.