退火对溶胶-凝胶法CoFe_2O_4薄膜结构与磁性的影响

Effect of Annealing on the Microstructure and Magnetic Properties of CoFe_2O_4 Thin films Prepared by Sol-Gel Method

采用溶胶-凝胶法在Si(001)基片上制备了CoFe2O4(CFO)薄膜,对样品进行不同温度的快速退火处理,并采用X射线衍射(XRD)、原子力显微镜(AFM)、振动样品磁强计(VSM)对薄膜进行微结构与磁性能分析。结果表明,薄膜退火温度在450℃及以上时生成无择尤取向的单一尖晶石相。随着退火温度上升,薄膜的晶化程度增高,Ms增大。650℃左右退火薄膜晶粒达到单畴临界尺寸,导致Hc随着退火温度的继续上升而逐渐下降。EDS分析表明,成膜后的化学计量比偏移很小。

CoFe2O4 （CFO） thin films were synthesized on Si （001） substrates by sol-gel method followed by short annealing at different temperatures. The microstructure and magnetic properties of the samples were analyzed and measured by XRD, AFM, VSM and EDS, respectively. The experiment results showed that the films annealed at and above 450℃ have only a single phase of the spinel structure without any preferred crystalline orientation. The crystallization degree and the Ms of the CFO thin films increase slowly with the increase of annealing temperature. The grain size achieves the single-domain critical size at about 650℃, which causes decrease in Hc with the rise of annealing temperature. The EDS analysis showed that the films have a very small deviation from stoichiometric composition..