[Seminar] Szemináriumok - Seminars: Kocsis Vilmos

[Szeminárium koordinátor]

SZFI SeminarKocsis VilmosCenter for Emergent Matter Science, RIKEN (host: Asbóth János)Electric field control of magnetization and the magnetoelectric effect in Y-type hexaferrite single crystalsMonday, 6 January 2020, 10:00, KFKI Campus, Bldg. 1, 2nd floor, Conference RoomMagnetoelectric materials have the potential to enhance the high reliability of magnetic memory devices with higher speed and ultra-low power consumption. In the trigonal Y-type hexaferrites, the magnetoelectric properties are attributed to the so-called FE3 phase with co-existing ferrimagnetic and ferroelectric orders. In the Al-doped Y-type hexaferrite, (Ba,Sr)2Co2Fe11AlO22, the FE3 phase can be stabilized as a metastable state close to room temperature, as shown by former neutron diffraction and magnetic field induced polarization measurements. In this presentation, we demonstrate that by appropriate chemical doping the FE3 phase can be fully stabilized, as a further step towards room temperature magnetoelectric memory devices. The ferrimagnetic and ferroelectric domains have considerable coupling even at room temperature, and the direct (P-H) and inverse (M-E) magnetoelectric effects have been observed up to room temperature. Using magnetic force microscopy, manipulation of the magnetic domain pattern for the application of electric field is directly visualized. We have found that the magnetization switching is realized via the propagation of two kinds of domain walls; parallel and perpendicular to the applied electric field. Using the combination of high electric and magnetic fields, we have also investigated the isothermal switching between two ME states of the FE3 phase. We discuss these new findings in terms of a possible way to evaluate the stability of the ME state in multiferroic materials. Minden érdeklődőt szívesen látunk! - Everyone is welcome to attend.Róbert Juhászszfi-seminar at wigner.mta.hu
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