Magnetic Properties of Ion Beam Deposited CoPt and CoCrPt Films for Hard Bias Application in High Density Magnetoresistive Heads

We have observed a 30% of enhancement in coercivity, [H.sub.c], or a 40% increase in remnant magnetization in ion beam deposited (IBD) Cr/CoPt films as compared to IBD Cr/CoCrPt films. In addition, the magnetic properties of these hard bias films exhibit a strong dependence of on substrate and underlayer. Higher coercivity values associated with enhanced hcp Co (10??0) crystallographic orientation were measured in films grown on substrates in the preference order of glass, Si/[Al.sub.2][O.sub.3] and Si. CoPt films grown on CrV underlayer show lower [H.sub.2] values than films deposited on Cr underlayer. [H.sub.c] exhibits a maximum with increasing Cr underlayer thickness for both Cr/CoPt and Cr/CoCrPt films. This Cr thickness dependence of [H.sub.2] is correlated well with that of Co (10??0)/(0002) x-ray diffraction peak intensity ratio, indicating the role of crystallographic texture in control of coercivity of IBD hard bias films. Index Terms--IBD, Hard bias film, Microstructure, MR recording head.