插入Bi层对NiFe/Cu/NiFe/FeMn自旋阀多层膜交换耦合的影响

EFFECT OF INSETTING Bi LAYERS ON THE EXCHANGE COUPLING OF SPIN-VALVE NiFe/Cu/NiFe/FeMn

对于Ｔａ/ＮｉＦｅ/Ｃｕ/ＮｉＦｅ/ＦｅＭｎ/Ｔａ自旋阀多层膜,Ｃｕ原子偏聚到ＮｉＦｅ/ＦｅＭｎ界面将导致自旋阀多层膜中ＮｉＦｅ/ＦｅＭｎ的交换耦合场Ｈｅｘ下降．然而,少量的表面活化原子Ｂｉ被沉积到Ｃｕ层和被钉扎ＮｉＦｅ层之间,Ｃｕ原子在ＮｉＦｅ/ＦｅＭｎ界面的偏聚可以被抑制:而且,更重要的是Ｔａ/ＮｉＦｅ/Ｃｕ/ＮｉＦｅ/ＦｅＭｎ/Ｔａ自旋阀多层膜中的交换耦合场Ｈｅｘ可以被有效地提高．

Experimental results show that Cu atoms can float out or segregate to the NiFe/FeMn interface for Ta/NiFe/Cu/NiFe/FeMn/Ta spin-valve multilayers, which results in a fall of the exchange coupling field (Hex) of NiFe/FeMn in the spin-valve multilayers. However, when a small amount of Bi atoms are deposited between Cu and pinned NiFe layer for the spin-valve multilayers, the Cu atoms' segregation to the NiFe/FeMn interface can be suppressed. At the same time, the Hex of NiFe/FeMn in the spin-valve multilayers with a Bi insetting layer can be effectively increased.