Y-GdIG系单晶铁氧体的磁性、铁磁共振和穆斯堡尔效应研究

THE MAGNETIC PROPERTIES, FERROMAGNETICRESONANCE AND MOSSBAUER EFFECT OFY-GdIG SINGLE CRYSTAL SYSTEM

本文在较宽温度范围内系统地研究了Y_(3-x)Gd_xFe_5O_(12)单晶体的饱和磁矩、铁磁共振和穆斯堡尔效应谱随成分和温度的变化,用亚铁磁理论解释了不同成分的热磁曲线及抵消点的变化,理论计算和实验结果符合较好.比较了几种铁磁共振线宽理论的计算结果,发现以亚铁磁共振理论加以适当条件后与实验结果较符合;发现Y^(3+)和Gd^(3+)在十二面体晶位中的代换,对四面体和八面体晶位中的Fe^(3+)的穆斯堡尔谱参量无明显影响;观测到代表四面体和八面体晶位中Fe^(3+)的谱线在磁有序区又再分成两组亚谱.

The dependence of the saturation magnetic moment, ferromagnetic resonance (FMR) and Mossbauer effect on the composition and temperature for the Y3-xGdxFe5O12 single crystal system with x=0, 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 have been studied at a wide range of temperature. The variations of thermo-magnetic curves and compansation points with composition are explained by the theory of ferrimagnetism. The theoretically calculated results agree well with those of experiments. The line-widths of FMR for several theories are evaluated. It is found that the experimental results can be well explained by the phenome-nological theory of ferrimagnetic resonance with some reasonable assumptions. It is also tcund that the substitution of Gd3+ for Y3+ ions in the dodecahedral site has hardly any significant influence on the Mossbouer parameters of Fe3+ ions in the tetrahedral and octahedral sites, whose spectra can be resolved into two subspectra again.