NiO/CoFe双层膜的交换机制研究

通过改变制备NiO薄膜的氩气压和衬底材料,研究了NiO的结构、表面粗糙度对NiO/CoFe双层膜交换耦合场Hex的影响.实验表明完全自旋未补偿面与交换耦合场的产生没有直接联系,但交换耦合场Hex与界面状况密切相关.增大NiO的表面粗糙度会使交换耦合场Hex减小.应用随机场理论在考虑了实际界面存在的粗造度、杂质和缺陷等实际情况下,正确地预测了交换耦合场的数量级,而且对交换耦合场与铁磁层厚度tFM、反铁磁层厚度tAFM以及交换耦合场的温度特性等实验结果做出了合理解释.并应用随机场模型对反铁磁/铁磁双层膜中铁磁层矫顽力Hc与铁磁层厚度tFM的关系进行了定量计算,发现矫顽力Hc与铁磁层厚度1/tFM成正比,这一结果表明理论计算与我们的实验数据符合得很好.

Exchange Mechanism of NiO/CoFe Bilayers

Influence of NiO texture and its interfacial roughness on the exchange coupling field H ex ,in the NiO/CoFe bi-layers grown by magnetron sputtering,was studied by varying the argon pressure and substrate materials.The results show that H ex of the bi-layers strongly depends on the interfacial roughness instead of the NiO(111) texture and that H ex decreases with the roughening of the interface.Possible mechanism explaining the relationship between interfacial roughness and H ex was tentatively discussed with a random-field model.The calculation agrees well with our experimental results.