添加AlN对FePt薄膜结构和磁性的影响

采用射频磁控溅射制备了FePt(50nm)和FePt(2,3,5nm)/AlN(1nm)]n膜,之后在550℃退火30min,研究了周期数(n)和AlN含量对FePt/AlN]_n系列多层膜结构及磁性的影响.结果表明,多层膜的矫顽力和矩形比均在n=8时出现较大值;周期数的增大会引起晶粒尺寸的长大;AlN的加入不但可以抑制FePt粒子的长大,使晶粒体积(V_grain)和磁激活体积(V*)趋于一致,而且还能有效地降低晶粒间交换耦合作用,并且AlN含量越大,晶粒间交换耦合作用的程度越弱.

Eifect of AIN on the Structure and Magnetic Properties of FePt Thin Films

FePt(50nm) and FePt(2,3,5nm)/AlN(1nm)]_n films were prepared by RF magnetron sputtering technique, then annealed at 550℃ for 30min. The effect of the number of bilayer repetitions (n) and AlN content on structure and magnetic properties of various FePt/AlN multilayers was studied. The highest coercivity and squareness of FePt/AlN multilayers annealed at 550℃ were obtained for n=8. The grain size of the FePt/AlN films by post-annealing increases with increasing n. Introducing the nonmagnetic AlN not only hinders the growth of FePt particles, but also reduces the intergrain exchange interactions of the FePt/AlN films. And the interactions are decreased as AlN content is increased. Grain size (V_grain) has almost the same size as magnetic activation volume (V*) due to the addition of AlN in films by post-annealing.