Title :
Temperature Dependence of Exchange Bias and Coercivity in (Ga,Mn)As–MnO Bilayer Structures
Author :
Ge, Zhiguo ; Lim, Weng-Lee ; Cho, Yong-Jin ; Liu, Xinyu ; Furdyna, Jacek K. ; Dobrowolska, Malgorzata
Author_Institution :
Dept. of Phys., Notre Dame Univ., IN
fDate :
6/1/2007 12:00:00 AM
Abstract :
In this paper, we report a systematic study on the temperature dependences of the exchange bias (EB) field HEB and coercivity HC in (Ga,Mn)As-MnO bilayers via magnetotransport measurements. Structures of (Ga,Mn)As-Mn were grown by molecular beam epitaxy, and then oxidized to obtain a top layer of MnO. Different methods were used to oxidize the Mn, and their effects on the behavior of HEB and HC were studied. It is a striking result that, once the structure is field-cooled from room temperature to 4.2 K, HEB retains its value even after warming the structure to 130 K, indicating that the exchange coupling sustains the ordering in MnO above the Neacuteel temperature TN (110 K) of bare MnO
Keywords :
III-V semiconductors; Neel temperature; coercive force; exchange interactions (electron); ferromagnetic materials; gallium arsenide; galvanomagnetic effects; magnetic epitaxial layers; manganese compounds; semimagnetic semiconductors; (Ga,Mn)As-MnO bilayer structure; 293 to 4.2 K; GaMnAs-MnO; Neel temperature; coercivity; exchange bias; exchange coupling; magnetotransport; temperature dependence; Annealing; Antiferromagnetic materials; Coercive force; Hall effect; Magnetic field measurement; Magnetic semiconductors; Molecular beam epitaxial growth; Oxidation; Physics; Temperature dependence; Diluted magnetic semiconductor; exchange bias; planar Hall effect;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2007.893348
