https://doi.org/10.1140/epjb/e2012-20985-5
Regular Article
Critical angles in angular dependent magnetization reversal of exchange biased Co/FeMn bilayers
National Laboratory of Solid State Microstructures and Department
of Physics, Nanjing, University, Nanjing
210093, P.R.
China
a e-mail: jdu@nju.edu.cn
Received:
4
December
2011
Received in final form:
21
February
2012
Published online:
22
May
2012
Magnetization reversal behavior in the exchange biased Co/FeMn bilayers with collinearly aligned ferromagnetic (FM) intrinsic anisotropy and induced interfacial anisotropy was investigated by angular resolved magnetic hysteresis loops measurements, and special attention was paid to the magnetization signals recorded perpendicular to the external magnetic field direction (My). During the angular magnetization reversal process, two critical angles were clearly observed. Around the easy axis, the magnetization reverses in a full circle, i.e., two My peaks appear with opposite signs. In contrast, above a certain critical angle αc1, the magnetization reverses only in one semicircle, i.e., My always remains positive or negative. Above another critical angle αc2, the heights of the two My peaks becomes equivalent. The angular dependence of exchange bias (ADEB) was also carefully investigated. In order to understand the experimental reversal behaviors clearly, numerical simulations were performed based on a modified Stoner-Wohlfarth (S-W) model considering the collinear anisotropies in current samples. The calculated results unambiguously show that the angular dependent reversal behavior as well as the occurrence of two critical angles is originated from the strength competition between the FM intrinsic anisotropy and the field cool induced interfacial exchange anisotropy.
Key words: Solid State and Materials
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag, 2012
