MNXPT1-X - A NEW EXCHANGE BIAS MATERIAL FOR PERMALLOY

We report exchange biasing of Permalloy in as-grown MnxPt1-x/Permalloy structures grown by coevaporation in ultra-high vacuum. Polycrystalli ne and epitaxial structures with x between 0.35 and 0.75 were studied. X-ray diffraction confirms the presence of chemical ordering in the M nxPt1-x films (grown at 200 degrees C) in as-grown polycrystalline and epitaxial structures. An interfacial coupling energy of 0.032 erg/cm( 2) is found for structures where the MnxPt1-x (x = 0.56) is grown at 2 00 degrees C onto epitaxial Permalloy (001). Polycrystalline structure s have a smaller (0.027 erg/cm(2)) interfacial coupling energy. No exc hange bias is observed for films with x less than or similar to 0.4. T he blocking temperature, for a sample with x = 0.56, is >500 K. (C) 19 97 American Institute of Physics.