Low Temperature Physics: 33, 957 (2007); https://doi.org/10.1063/1.2747073 (8 pages)
Fizika Nizkikh Temperatur: Volume 33, Number 11 (November 2007), p. 1260-1270 ( to contents , go back )
Exchange anisotropy of FeNi/FeMn polycrystalline films with asymmetric hysteresis loop
D.N. Merenkov, A.N. Bludov, S.L. Gnatchenko
B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine 47 Lenin Ave., Kharkov 61103, Ukraine
M. Baran and R. Szymczak
Institute of Physics, Polish Academy of Sciences, 32/46 Al. Lotnikow, Warsaw 02-688, Poland
Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne IL60439, USA
Received March 16, 2007
The process of magnetization reversal of a polycrystalline FeNi(50 E)/FeMn(50 E) film prepared in magnetic field is investigated in a temperature interval 25–300 K. The external field in the film plane is directed along the easy or hard axis of the ferromagnetic layer. The magnetization reversal in the film along the easy axis causes a strong asymmetry of the hysteresis loop in addition to the exchange bias. As the temperature is lowered, the asymmetry becomes more distinct and the bias increases. When the external field is applied along the hard axis, the field dependence of the film magnetization are symmetric and non-biased. Magnetization reversal is considered within the model allowing for the high-order exchange anisotropy in polycrystalline films. It is shown that the observed strong asymmetry of the hysteresis loop is related to the formation of an angular phase and to the existence of a metastable state. The lowering of the film tempereture leads to the extension of the field interval of the angular phase, which occurs due to increase in the constants of exchange anisotropy.
PACS: 75.70.Cn Interfacial magnetic properties;
Key words: exchange anisotropy, asymmetry of hysteresis loop, magnetization reversal, angular phase.