Magnetic Properties and Crystal Structures of Sputtered CoFe Films

Sputtered Co-(15-19 at%) Fe films were prepared, varying the Ar gas pressure and substrate temperature as parameters. The relationships between the film magnetic properties and crystal structure were investigated. Films with an fcc phase (111) preferred orientation showed relatively high H
c
values of more than 8 Oe and a B
s
of about 19 kG. Films with a bec phase (110) preferred orientation showed low H
c
values of 2 to 3 Oe, comparable to the values for single-layered Fe-base films, and a B
s
of about 21 kG. It was verified that this difference in H
c
is not attributable to differences in internal stress or in crystallite size.