Nanoscale control of exchange bias with BiFeO3 thin films.
We demonstrate a direct correlation between the domain structure of multiferroic BiFeO3 thin films and exchange bias of Co 0.9Fe 0.1/BiFeO3 heterostructures. Two distinct types of interactions - an enhancement of the coercive field ( exchange enhancement) and an enhancement of the coercive field combined with large shifts of the hysteresis loop ( exchange bias) - have been observed in these heterostructures, which depend directly on the type and crystallography of the nanoscale ( approximately 2 nm) domain walls in the BiFeO3 film. We show that the magnitude of the exchange bias interaction scales with the length of 109 degrees ferroelectric domain walls in the BiFeO 3 thin films which have been probed via piezoresponse force microscopy and X-ray magnetic circular dichroism.
Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA. lwmartin@lbl.gov
Lane W
LW
Martin
Ying-Hao
YH
Chu
Mikel B
MB
Holcomb
Mark
M
Huijben
Pu
P
Yu
Shu-Jen
SJ
Han
Donkoun
D
Lee
Shan X
SX
Wang
R
R
Ramesh