室温生长MgO底层诱导(001)取向FePt薄膜的有序化过程对FePt成分的依赖  

Composition dependence of L1_0 ordering of FePt(001) thin films on MgO underlayer grown at room temperature

作　　者：张丽娇[1] 蔡建旺[1] 

机构地区：[1]中国科学院物理研究所磁学国家重点实验室,北京100080

出　　处：《物理学报》2007年第12期7266-7273,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:50271081)资助的课题.~~

摘　　要：室温下通过磁控溅射在表面热氧化的Si基片上生长了MgO/FexPt100-x双层膜和FexPt100-x单层膜系列样品,FexPt100-x的原子成分x=48—68.研究了热处理前后不同成分FePt薄膜的晶体结构和磁性的变化,尤其是MgO底层的引入对FePt的晶体结构和磁性的影响.实验结果显示,直接生长在基片上的FePt薄膜具有较强的(111)织构,而经过MgO底层诱导,所有不同成分的制备态FePt薄膜都表现出一定的(001)取向.热处理后,单层膜样品的强烈(111)织构基本不变,当Fe和Pt接近等原子比即52∶48时,薄膜最容易发生有序化;对于生长在MgO底层的FePt薄膜,所有样品的(001)织构在退火后显著增强,有序化对FePt成分的依赖完全不同于单层膜的情形.当Fe和Pt原子比为59∶41时,生长在MgO底层上的FePt薄膜最容易有序化,表现出非常好的垂直易磁化特性,通过MgO底层对FePt薄膜微结构进而对其有序化的影响,对此进行了解释.We investigated the effect of extensive compositional change on the structure and magnetic properties of the post-annealed FexPt100-x （48 ≤ x ≤ 68） thin films with and without MgO underlayer deposited at room temperature. It was found that, during annealing, the FePt films on MgO underlayer with Fe-rich composition around 59at% exhibit much faster ordering than those with other compositions although the single layer FePt films were found to have the optimum composition for the chemical ordering of only slightly Fe-rich composition of 52at% of Fe. The film of MgO（ 10 nm）/Fe59 Pt41 （8 nm） after annealing at 600 ℃ for 30 min showed perpendicular magnetization with coercivity about 800 kA/m and the squareness was close to 1 due to the formation of （001） oriented ordering phase. The results of FePt thin films on MgO underlayer deposited at room temperature present a striking contrast with those of FePt grown on heated MgO single crystal substrate, where the optimum composition for the ordering was around 62at% of Pt. An interpretation on the observed experimental phenomena is given in this paper.

关 键 词：FePt(001)薄膜 L10相 

分 类 号：O484[理学—固体物理]