使用成分分别为MnFe2O4和ZnFe2O4的靶,使用射频溅射交替沉积制备了成分不同的Mn1-xZnxFe2O4薄膜,沉积薄膜所用基片分别为单晶硅Si(100),氧化的单晶硅SiO2/Si(100),ZnFe2O4为衬底的单晶硅ZnFe2O4/Si(100)及单晶氧化镁MgO(100),沉积态的薄膜为非晶结构,经550℃真空退火后可以得到MnZn多晶铁氧体薄膜.成分为Mn0.5Zn0.5Fe2O4的薄膜呈现了较好的磁性:相对高的Ms及低的Hc.以MgO(100)为基片薄膜的矫顽力最低,约为2148A/m.对基片材料对薄膜磁性的影响作了分析.认为铁氧体薄膜中应力导致的磁弹性各向异性对薄膜的矫顽力起着主导作用,选用合适的基片可使薄膜中晶粒细化至纳米尺度,晶粒间增强的交换耦合作用可对薄膜中的磁弹性各向异性做有效平均并使其降低,从而使MnZn铁氧体薄膜的软磁特性得到改善.
Mn1-xZnxFe2O4 films were prepared by alternative if-sputtering from targets of MnFe2O4 and ZnFe2O4. The films were deposited on substrates such as single-crystal Si(100), oxidized single-crystal Si(100), single-crystal Si(100) with ZnFe2O4 underlayer and single-crystal MgO( 100). The deposited films are amorphous. After annealing in vacuum furnace at 550℃, the polycrystalline Mn-Zn ferrite crystallizes. The film with composition of Mn0.5Zn0.5Fe2O4 shows better magnetic properties : high magnetization Me and lower coercivity He. The coercivity of the film deposited on MgO(100) substrate is the lowest. In this paper, the influences of substrate on film structure and the magnetic properties are investigated. It is believed that the magnetoelastic anisotropy resulting from stress in films dominates the coereivity of Mn-Zn ferrite films. The grain size may be refined to nanometer scale instrumentally by using suitable substrate; the stronger exchange coupling between grains would lead to a lower magneto-elastic anisotropy by averaging to the grains. Therefore, the soft magnetic properties of Mn-Zn ferrite films are improved.