Structural and magnetic properties of FePt films grown on Cr1-xMox underlayers

FePt films were deposited on Cr1-xMox underlayers by dc magnetron sputtering. The effects of the Mo content in the underlayers, underlayer thickness, substrate temperature, and FePt film thickness on the structural and magnetic properties of the FePt films were studied. Experimental results showed that the (200) textured Cr90Mo10 film was a promising underlayer for promoting the growth of the L1(0) FePt films with (001) preferred orientation at relatively low temperatures. With the Cr90Mo10 underlayers, the ordering process of the FePt films could start at 200 degrees C. Both the ordering degree and the out-of-plane coercivity (H-c) of the FePt films increased with an increase in substrate temperature. When the substrate temperature was >= 250 degrees C, the FePt films grown on the Cr90Mo10 underlayers could have the (001) preferred orientation. The FePt films grown on the Cr90Mo10 underlayers at different temperatures showed a continuous microstructure. The out-of-plane coercivities H-c decreased while the ordering degree increased with increased FePt film thickness, which could be due to the variation of the magnetic reversal mechanism from rotation predominant mode to domain wall motion predominant mode.