Formation of ordered FePt(001) texture with reduced diffusion length

Abstract

Samples with glass/CrRu(90 nm)/Pt(2 nm)/FePt(20 nm) film structure were sequentially planetary-sputtered at an in situ heating temperature of 350 °C to investigate the effect of sputtering rate on the ordering of Ll0 -FePt (001) films. The degree of chemical ordering was enhanced by lowering the sputtering rate of the FePt layer. The slow sputtering process also promoted the formation of the (001) preferred orientation by improving epitaxial growth, because the thickness of the Fe and Pt layers in each revolution become smaller as the sputtering rate was reduced. Therefore, the diffusion lengths of the Fe and Pt atoms required for migration into the lattice sites became shorter. The sputter parameters can be optimized to form ordered FePt (001) films with a high magnetic squareness ratio and large coercivity at 300 C, which is 50 C lower than in previous reports. The results herein provide useful information on the fabrication of FePt films with perpendicular anisotropy at low temperatures in media use. © 2009 IEEE.