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

Volume

43

Issue

6

fYear

2007

fDate

6/1/2007 12:00:00 AM

Firstpage

3013

Lastpage

3015

Abstract

In this paper, we report a systematic study on the temperature dependences of the exchange bias (EB) field HEB and coercivity H_C 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 H_EB and H_C were studied. It is a striking result that, once the structure is field-cooled from room temperature to 4.2 K, H_EB 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 T_N (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;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/TMAG.2007.893348

Filename

4202731