Cu掺杂对Fe/Si多层膜的层间耦合和负磁电阻效应的影响

Cu doping effect on the interlayer coupling and negative MR of Fe/Si multilayers

研究了 Cu掺杂对 Fe/Si多层膜的层间耦合和负磁电阻效应的影响。在用磁控溅射方法制备的 Fe/Si多层膜中，发现在 Si的标称厚度 tSi=1.9 nm附近存在一较强的反铁磁耦合（ AFM）峰和与之相对应的负磁电阻峰。在 Si层中掺入 6％的 Cu后，发现反铁磁耦合峰的饱和场显著降低，峰宽变窄，峰位略向较厚方向移动。掺杂后磁电阻峰的缝宽和峰位变化与 AFM峰相似，而磁电阻峰值则略有下降。在液氮温度 T=77 K下，掺杂前后具有负磁电阻效应的多层膜样品的电阻率都降低，而磁电阻效应和饱和场均增大。实验结果表明，用磁控溅射方法制备的 Fe/Si多层膜的层间耦合机制和磁电阻效应的机制与磁性金属 /非磁金属多层膜的层间耦合及磁电阻效应的机制是一致的。

Two series of [Fe(3 nm)/Si(tSi)]30 and [Fe(3 nm)/Si94Cu6(tSiCu)]30 Multilayers were prepared by magnetron sputtering method, and the Cu doping effect on the interlayer coupling and negative magnetoresistance of Fe/Si multilayers was studied. It was found that a strong antiferromagnetic (AFM) coupling existed for [Fe(3 nm)/Si(tSi)]30 multilayers with tSi= 1nm to 3nm. After doping 6％ Cu in the Si spacer the AFM coupling peak shifted to thicker spacer with narrower peak width and the saturation field decreased significantly, while the MR peak decreased slightly. Both saturation field and value of MR ratio increased and the resistance decreased at 77 K for the Cu doped and without doped samples with AFM coupling. Our data suggest that the mechanisms of AFM coupling and GMR effect in our sputtered Fe/Si multilayers are the same as in metal/metal system.