膜厚对NiFe单层膜及NiFe/FeMn双层膜性能的影响对比研究

Comparative study on influnece of film thickness on the properties of NiFe monolayers and NiFe/FeMn bilayers

采用直流磁控溅射法在Si(111)基片上制备不同厚度的NiFe单层膜、NiFe/FeMn双层膜,结合原子力显微镜(AFM)、振动样品磁强计(VSM)及电子顺磁共振(EPR)波谱仪研究了纳米膜的微观形貌、表面粗糙度、静磁性能及微波磁性能。结果表明,相对于NiFe单层膜,反铁磁性覆盖层FeMn的引入,使NiFe/FeMn双层膜的共振场(Hres)下降,与自旋波共振相关的有效交换场得以提升,说明在一定的外加稳恒磁场下,利用铁磁/反铁磁(FM/AF)多层膜结构所产生的钉扎效应能够提高薄膜的共振频率。在20~70 nm的NiFe薄膜厚度范围内,单层膜的共振场为1289~1354Oe,而双层膜的共振场降至1089~1118 Oe。

NiFe monolayers and NiFe/FeMn bilayers were deposited on the substrate of Si(111)by direct current(DC)magnetron sputtering method.The surface morphology,roughness and magnetic property were measured by atomic force microscope(AFM),vibrating sample magnetometer(VSM)and electronic paramagnetic resonance(EPR)spectrometer,respectively.The results show that,compared with NiFe monolayers,due to the introduction of antiferromagnetic cover layers(FeMn),the resonance field(Hres)of NiFe/FeMn bilayers has been reduced obviously,which meant the effective exchange field related to spin wave resonance has been enhanced.And pinning effect has worked.As a result,if the applied steady magnetic field is constant,the corresponding resonance frequency can be enhanced by the pinning structure.As the thickness of NiFe films changing from 20 nm to 70 nm,the resonance field(Hres)of pinning multilayers changes from 1089 Oe to 1118 Oe,while that of corresponding monolayers varies from 1289 Oe to 1354 Oe.