磁性颗粒膜的铁磁共振

Ferromagnetic Resonance in Magnetic Granular Films

从理论上分析了颗粒膜在铁磁共振(FMR)场Hr上由于颗粒形状、尺寸、取向、百分含量及温度的效应.分析了斜置共蒸发沉淀而成的CoxAg1-x颗粒膜(百分含量(0.2<x<0.85)、体积填充因子f(0.17<f<0.85))与Hr的关系,在室温下FMR的Hr(f)-f曲线显示,在系统的逾渗点f=fp≈0.3时产生突变,这变化与铁磁(FM)颗粒的聚集增长相关联,这种关联是在f>fp时与单一超顺磁相(SPM)颗粒比较.另外,对Fe-S iO2颗粒膜其Hr(f)-f曲线的分析也显示在逾渗点f=fp≈0.28时产生不连续的跃变.磁性颗粒膜的这一性质提供了有效探明第一类磁逾渗材料的相转变途径.

This paper theoretically analyzes the effects of granular size, shape, orientation, concentration and temperatures on the ferromagnetic resonance （FMR） field Hτ in magnetic granular films. The relationship between CoxAg1-x granular film （0.2 〈 x 〈 0.85 ） prepared by oblique coevaporation, bulk filling factorf （0.17 〈 f 〈 0.85 ） and Hτ is also analyzed. At room temperatures, Hτ （f） - f curve of FMR shows that there is an abrupt change at the percolation point f=fp≈0. 3, which is associated with the aggregation and growth of FM granules. This association is compared with SPM granules at f 〉fp, Besides, the analysis for the Hτ （f）- f curve of Fe-SiO2 granular film indicates that there are uncontinuous abrupt changes at f=fs,≈0.28. This property offers a new way to effectively test the phase transition of the first kind of magnetic percolation materials.