Thermal Decay and Reversal of Exchange Bias Field of CoFe/PtMn Bilayer after Ga+ Irradiation

• 来源期刊: 中国物理快报（英文版）
• 年，卷（期）: 2011,（5）
• 页码范围: 238-241
• 页数: 4页
• 语种: 英文
• DOI: 10.1088/0256-307X/28/5/057502

摘要

An applied field is used to perform Ga+ ion irradiation on a CoFe/PtMn bilayer.Effects of the applied field and energy transfer between Ga+ ions and antiferromagnetic(AFM) atoms on the exchange bias field Hex are investigated.A partially reversed Hex is found in CoFe/PtMn specimens irradiated at a dose of 1 × 1014 ions/cm2 with an applied field anti-parallel to the original exchange bias direction.We believe that the rapid energy transfer and local temperature increase originating from the interaction between Ga+ ions and AFM atoms result in spin reversal and the formation of reversed AFM domains when specimens are irradiated with anti-parallel fields.The decrease in Hex when annealing the film in a negative saturation field indicates a thermal decay process.The AFM moments are reversed by thermal activation over an energy barrier distribution,which may change in some way as the temperature increases.