ZnO:Mn稀磁薄膜结构和铁磁特性分析  

Structural and Ferromagnetic Characteristics of ZnO:Mn Thin Films

作　　者：于威[1] 张丽[1] 张子才[2] 杨丽华[1] 滕晓云[1] 张锦川[1] 傅广生[1] 

机构地区：[1]河北大学物理科学与技术学院,保定071002 [2]河北大学工商学院,保定071002

出　　处：《人工晶体学报》2009年第3期685-688,共4页Journal of Synthetic Crystals

基　　金：河北省自然科学基金(No.E2006001006)

摘　　要：采用脉冲激光沉积技术在蓝宝石衬底上制备了不同Mn掺杂浓度的ZnO薄膜(ZnO∶Mn),研究了与生长相关的浅缺陷能级对薄膜磁性的作用。结果表明:所制备的ZnO∶Mn薄膜均具有高度c轴择优取向,且具有室温铁磁性。随Mn含量增加,薄膜结晶质量逐渐提高,晶粒尺寸明显增大,单位磁性离子磁矩逐渐减小。薄膜所显示出的铁磁性可归结为材料结构缺陷的本质反映。薄膜导电特性变化反映了薄膜生长过程所决定的晶粒内部和晶粒边界缺陷密度变化的竞争,与此对应,激活能的变化反映了晶粒内部费米能级位置先升高而后降低。薄膜的载流子传输在低温下满足变程跳跃电导机制,该机制和材料的铁磁性紧密相关。近邻Mn离子比例的增加将对薄膜铁磁性的减小产生贡献。Mn-doped ZnO （ZnO： Mn） thin films with different content of Mn were prepared on sapphire substrates by pulsed laser deposition. The effect of shallow defect energies related to crystal growth on the magnetic properties of the films has been investigated. All the ZnO： Mn films have a perfect c orientation and show ferromagnetic at room temperature. With increasing Mn content, the crystal quality improves, grain size increases, and the saturation magnetic moment per Mn atom decreases. The ferromagnetic is attributed to the intrinsic characterize of the structure defects in films. The variation of conductivity reflects the competition of the intragranular and grain boundary defect density decided by growth procedure. Correspondingly, the change of activation energy reflects that Fermi level in the grain first increases and then decreases. The carrier transfer in the films at low temperatures meets the variable- range hopping mechanism, which is closely related to ferromagnetism. Increase in proportion of neighbor Mn ions is contributed to the decrease of the saturation magnetic moment per Mn atom.

关 键 词：ZnO∶Mn薄膜 室温铁磁性 结构缺陷 

分 类 号：TB7[一般工业技术—真空技术]