纳米复合Fe-R-O(R=Hf,Nd,Dy)薄膜面内铁磁共振研究  

In-plane ferromagnetic resonance in nano-composite Fe-R-O(R=Hf, Nd, Dy) films

作　　者：杜军[1] 孙亮[1] 盛雯婷[1] 游彪[1] 鹿牧[1] 胡安[1] M.M.CorteReal J.Q.Xiao 

机构地区：[1]南京大学物理系 [2]Department of Physics and Astronomy

出　　处：《物理学报》2004年第7期2352-2356,共5页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:10021001);国家重点基础研究发展规划项目(批准号:2001CB610602);江苏省自然科学基金(批准号:BK2001203)资助的课题~~

摘　　要：用反应溅射方法制备了Fe R O(R =Hf,Nd ,Dy)薄膜 ,并在 4 0 0℃时对样品进行退火处理 ,x射线衍射和电子衍射结果显示纳米量级的Fe晶粒镶嵌在非晶氧化物基质中 .用面内铁磁共振技术仔细测量了样品的共振吸收谱 ,并分析了局域磁化强度Ms 与晶粒尺寸的关系 .制备态样品呈现出显著的面内单轴各向异性 ,退火后单轴各向异性显著减弱 ,取而代之的是较弱的磁晶各向异性 .利用公式 (ω γ) 2 =(Hres+HK) (Hres+HK +4πMs)求出局域磁化强度Ms,它随晶粒尺寸减小而减小 ,在晶粒尺寸为 5nm时仅约为Fe体材料饱和磁化强度的 30 % .局域磁化强度与根据Fe的体积百分比算出的体磁化强度相比偏小 ,并与晶粒尺寸的倒数呈线性关系 ,说明在晶粒表面存在较强的磁矩钉扎效应 .Fe-R-O (R=Hf, Nd and Dy) films were made by reactive sputtering technique and annealed at 400℃. X-ray diffraction and electron diffraction show that nanometer scale Fe grains are embedded in amorphous R-oxide matrix. In-plane ferromagnetic resonance was systematically carried out to measure the in-plane resonance absorption spectra and utilized to analyze the relationship between the local magnetization and grain size. The as-deposited samples show obvious uni-axial anisotropy, while annealed samples display weak magnetic crystalline anisotropy at the expense of weakening the uni-axial anisotropy. The local magnetization was calculated based on the formula. (ω/γ)2=(H res+H K)(H res+H K+4πM s).It decreases with decreasing grain size, being as only about 30% of the saturation magnetization of bulk Fe. It is also smaller than the bulk magnetization calculated according to the volume ratio of Fe. The linear dependence on the inverse of the grain size indicates a strong surface moment pinning effect.

关 键 词：铁磁共振 局域磁化强度 单轴各向异性 磁晶各向异性 纳米复合薄膜 

分 类 号：O484[理学—固体物理]