TY - JOUR
T1 - Anisotropic AC Magnetic Susceptibility in (Ga,Mn)As Films
AU - Li, Xiang
AU - Dong, Sining
AU - Yoo, Taehee
AU - Liu, Xinyu
AU - Lee, Sanghoon
AU - Furdyna, Jacek K.
AU - Dobrowolska, Margaret
N1 - Publisher Copyright:
© 1965-2012 IEEE.
Copyright:
Copyright 2018 Elsevier B.V., All rights reserved.
PY - 2015/11/1
Y1 - 2015/11/1
N2 - We report a systematic investigation of ac magnetic susceptibility in (Ga,Mn)As films as a function of temperature and magnetic field, carried out in parallel with dc magnetization measurements. The temperature dependence of ac susceptibility χac shows anisotropic behavior: 1) a single peak in χac is observed close to TC for the [110] orientation of the driving ac field; 2) a single peak is also seen close to 22 K for the field along [110]; and 3) peaks at both these temperatures are observed for the field applied along [100]. A detailed analysis of the ac and dc data unambiguously indicates that the peak near TC is related to the paramagnetic-to-ferromagnetic phase transition, with the ferromagnetic domains nucleating with their easy axes aligned with the [110] direction, providing a clear picture of uniaxial domain behavior near TC. The peak near 22 K, on the other hand, is related to the onset of biaxial domain structure in (Ga,Mn)As induced by the competition between uniaxial and cubic anisotropy. More specifically, the ac susceptibility peak near TC involves 180° magnetization flips along the [110] easy axis of the domains, while the peak near 22 K originates from magnetization wobbling between two biaxial easy axes separated by a small angle.
AB - We report a systematic investigation of ac magnetic susceptibility in (Ga,Mn)As films as a function of temperature and magnetic field, carried out in parallel with dc magnetization measurements. The temperature dependence of ac susceptibility χac shows anisotropic behavior: 1) a single peak in χac is observed close to TC for the [110] orientation of the driving ac field; 2) a single peak is also seen close to 22 K for the field along [110]; and 3) peaks at both these temperatures are observed for the field applied along [100]. A detailed analysis of the ac and dc data unambiguously indicates that the peak near TC is related to the paramagnetic-to-ferromagnetic phase transition, with the ferromagnetic domains nucleating with their easy axes aligned with the [110] direction, providing a clear picture of uniaxial domain behavior near TC. The peak near 22 K, on the other hand, is related to the onset of biaxial domain structure in (Ga,Mn)As induced by the competition between uniaxial and cubic anisotropy. More specifically, the ac susceptibility peak near TC involves 180° magnetization flips along the [110] easy axis of the domains, while the peak near 22 K originates from magnetization wobbling between two biaxial easy axes separated by a small angle.
KW - Ferromagnetic semiconductors
KW - magnetic anisotropy
KW - magnetic domains and magnetic susceptibility
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U2 - 10.1109/TMAG.2015.2442513
DO - 10.1109/TMAG.2015.2442513
M3 - Article
AN - SCOPUS:84946222231
VL - 51
JO - IEEE Transactions on Magnetics
JF - IEEE Transactions on Magnetics
SN - 0018-9464
IS - 11
M1 - 07118705
ER -