Eur. Phys. J. B 78, 373-379 (2010)
https://doi.org/10.1140/epjb/e2010-10576-y

Shape-induced oscillation of exchange bias in the Co nanopillar with lateral oxidation

College of Sciences, Northeastern University, Shenyang, 110819, P.R. China

Corresponding author: ^a duanneu@126.com

Received: 26 July 2010
Published online: 29 November 2010

Abstract

A modified Monte Carlo Metropolis method is performed to simulate the hysteresis loops of a laterally oxidized Co nanopillar with an excised arc or an inclined circular plane. At low temperature after field cooling, an oscillatory exchange bias is observed with excised length or angle of inclination. However, the behaviors of coercivity exhibit a monotonous decrease with excision but an oscillation with tilt. The phenomena are intriguing and corroborated by means of the microscopic spin configurations and the magnetization reversal mechanisms. The occurrence of oscillatory exchange bias in such a Co/CoO composite nanopillar with direct exchange couplings is mainly because of the shape inducement in the nanopillar, which results in the energy fluctuations of interfacial coupling and the nonuniformity of domain distribution.