反铁磁耦合纳米体系磁特性的微磁学研究

Magnetic properties of antiferromagnetically exchange coupled nanometer system studied by micromagnetics

采用微磁学方法研究了磁层间反铁磁耦合强度对SyAF纳米体系磁特性的影响.当SyAF纳米体系上、下磁层间的反铁磁耦合强度不同时,SyAF纳米体系具有两种不同类型的磁滞回线.当磁层间反铁磁耦合强度较小时,体系的矫顽力随反铁磁耦合强度的增大而增大,反磁化机制为反磁化核的形成与传播的反转过程.而当磁层间反铁耦合强度较大时(>0.2×10-3J.m-2),体系的矫顽力基本不随反铁磁耦合强度变化,并且在剩磁态为稳定的单畴结构,反磁化机制为类一致反转过程.这类SyAF纳米体系更适合于作为磁信息器件中自旋阀的自由层.

The magnetic properties of antiferromagnetically exchange coupled nanometer system were investigated by micromagnetics simulation.When coupling strength between layers is weaker,the coercivity of SyAF nanometer system increases with the increasing of coupling strength between layers and the process of magnetization reversal,which is a inconsistent reversal,will accompany the emergence and multiplying of vortex domain.When coupling strength is stronger than 0.2×10^-3 J·m^-2 between layers,the coercivity of the system is small,and basically does not change with the anti-ferromagnetic coupling strength.Remanent state is a stable single-domain structure and the process of magnetization reversal will be a quasi-consistent reversal.Therefore,the SyAF nanometer system is used more suitable as a free layer of spin-valve in magnetic information devices.