通过超高真空反应磁控共溅射方法制备了CoTiO2薄膜样品,在退火过程中加入了紫外光照射,研究了退火温度在反应共溅法中对薄膜微结构和磁性能的影响。形貌和结构研究表明,随着退火温度的升高样品的表面颗粒尺度逐渐减小,温度越高越有利于磁性相的形成,且500℃退火温度下锐钛矿结构的衍射峰较明显,晶胞变大;磁滞回线显示出样品呈现铁磁性特征,并且随着退火温度的升高样品的磁化强度逐渐降低;热磁曲线测量显示有序温度高于120℃。退火过程中进行辐照干预的处理,发现在薄膜制备过程中对薄膜的结构及磁性有重要影响。铁磁性有可能是起源于在热处理过程中引起的磁性离子和氧空位导致的晶格缺陷。
In order to study the influence of annealing temperature on Co/TiO2 magnetic properties and microstructure,Co/TiO2 thin films have been fabricated by DC facing-target magnetron cosputtering and subsequently annealed in situ vacuum,in the process of annealing joined the UV irradiation. The morphologies and domain structures were observed by X-ray diffraction and scanning probe microscope. Magnetic properties were measured by physical property measurement system. The magnetization decreases with increase of annealing temperature in CoTiO2 thin films. The magnetization-temperature curve shows that the Curie temperatures of the samples are higher than 120 ℃. It seems that the ferromagnetic phase can originate from the defects of interactions between magnetic ions and oxygen vacancies in the TiO2 crystal lattice during the thermal treatment of the samples.