Title :
Co-existence of biquadratic and unidirectional anisotropy in IrMn/CoFe/FeOx/CoFe films
Author :
Lai, Chih-Huang ; Shen, Chih-Ta ; Huang, Po Hsiang ; Lin, H.J. ; Chen, C.T.
Author_Institution :
Dept. of Mater. Sci. & Eng., Nat. Tsing Hua Univ., Hsinchu, Taiwan
Abstract :
We observed the coexistence of biquadratic and unidirectional anisotropy in the CoFe layer by inserting the nano-oxide-layer FeOx in the IrMn/CoFe bilayers. Analyses of X-ray magnetic circular dichroism suggested that the FeOx possessed ferromagnetic components. Mixed valence states of Fe, Fe2+ and Fe3+ were observed in the FeOx layer, which implied that both antiferromagnetic and ferromagnetic components might co-exist in the FeOx layer. The uniaxial anisotropy in CoFe at 90° may originate from the interaction of CoFe with the antiferromagnetic components of the FeOx layer in the presence of interfacial magnetic roughness. The unidirectional anisotropy at 0° may result from the exchange biasing from the IrMn layer through the ferromagnetic components in the FeOxlayer.
Keywords :
exchange interactions (electron); magnetic anisotropy; magnetic circular dichroism; magnetic multilayers; IrMn-CoFe-FeO-CoFe; X-ray magnetic circular dichroism; antiferromagnetic components; biquadratic anisotropy; exchange biasing; ferromagnetic components; interfacial magnetic roughness; mixed valence states; nano oxide layer; uniaxial anisotropy; unidirectional anisotropy; Anisotropic magnetoresistance; Antiferromagnetic materials; Couplings; Iron; Magnetic anisotropy; Magnetic separation; Materials science and technology; Perpendicular magnetic anisotropy; Spin valves; Synchrotron radiation; Biquadratic coupling; FeO; exchange biasing; interlayer coupling; nano-oxide-layer;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2005.855225
