Effects Of Cobalt Substitution In L1(0) -(Fe,Co)Pt Thin Films

We have studied the effect of cobalt substitution in L1(0)-Fe1-xCox Pt films by means of x-ray magnetic circular dichroism (XMCD) and first-principles calculations. The magnetic moments of Fe (similar to 2.5 mu(B)) and Co (similar to 1.5 mu(B)) deduced using XMCD were almost unchanged upon Co doping, and the net magnetization decreases with increasing Co content. Calculation also showed that the 3d electrons that have been added by Co substitution occupy only spin-down bands.