ELFT HÍRADÓ

[Szeminárium koordinátor <szfi-seminar AT wigner.mta.hu>]

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