SmCo based sputtered films with CaCu5 and TbCu7 structures

Abstract

SmCo based films containing 20 at. % Fe and with Sm varying from 15.5 to 17 at. % have been synthesized to show the transition from ordered CaCu5 to disordered TbCu7 phase. For either phase, the demagnetization energy present during deposition can result in films with the crystallite c axes randomly splayed onto the film plane. It has been possible to synthesize the high anisotropy CaCu5 phase with either a (200) or (110) texture by adjusting the sputtering parameters to correspond to either a relatively high or relatively low surface mobility during the film deposition. It has been possible to synthesize ordered CaCu5 type films with very low values of BR(⊥)/BR(∥)=0.042. Previously, SmCo based single phase TbCu7 structure films have been synthesized with close to the usual high energy product 2–17 compositions of nominally 7 at. % Cu and 2 at. % Zr. The films have been characterized by vibrating-sample magnetometer and superconducting quantum interference device magnetometry, x-ray diffraction, and scanning electron microscope measurements for composition and film morphology. The films have been directly crystallized onto heated substrates so that the crystallite c axes are predominantly randomly aligned in the film plane. The crystal structures observed could be switched from the ordered CaCu5 to the disordered TbCu7 phase for small variations in the Sm concentrations.