Sol-gel法制备Co_xFe_(3-x)O_4薄膜的结构磁性及温度特性

Microstructure and magnetic properties and temperature dependence of Co_xFe_(3-x)O_4 films synthesized by Sol-gel method

采用溶胶-凝胶旋转包覆法在SiO_2衬底上制备了Co_xFe_(3-x)O_4(x=0.2～0.8)钴铁氧体薄膜。样品的磁性、结构及表面形貌分别采用振动样品磁强计(VSM)、X射线衍射仪(XRD)和原子力显微镜(AFM)进行测量与分析,并对Co_(0.8)Fe_(2.2)O_4薄膜进行了高温结构和磁性原位测量。室温测量结果表明,随Co^(2+)含量增加,样品中的尖晶石相衍射峰逐渐增强,至x=0.8时样品形成单一的尖晶石结构,同时获得较高的磁性,矫顽力达到1.56×10~5A/m,并且薄膜的晶粒得到细化。高温原位测量结果表明,在500℃高温下样品的线膨胀系数为1.3×10^(-5)K^(-1),表明Co_(0.8)Fe_(2.2)O_4薄膜结构具有良好的热稳定性。

CoxFe3-xO4 ferrite films（x = 0.2-0.8） have been synthesized on SiO2 substrates by the sol -gel spin - coating technique. The magnetic properties, microstructure and surface image of samples have been measured and analyzed by vibrating sample magnetometer, X - ray diffraction and atomic force microscope. Meanwhile, the magnetic properties and microstructure of Co0.8 Fe2.2O4 ferrite film have been situ measured at high temperature. The results at room temperature reveals that the peaks of spinel phase becomes higher gradually with increasing amount of Co^2＋ ions, and then single spinel phase exhibits when x = 0.8, so better magnetic properties of samples have been obtained, the coercivity reaches 1.56 × 10^5 A/m, and the grain of samples is refined. The in situ measurement at high temperature shows that the coefficient of linear expansion of Co0.8Fe2.2O4 film at 500 ℃ is 1.3 × 10 ^-5 K^-1 , the microstructures of cobalt ferrite films have good thermal stabilization.