Phase Composition and Physical Properties of the MnBiCr Films, Obtained by Ion-plasma Sputtering

The paper presents the results of investigations of phase composition and physical properties of the pure Mn, MnCr and MnBiCr films, obtained by ion-plasma sputtering. X-ray analysis and estimation of the size (L) of coherent-scattering regions (CSR) showed that in the pure Mn as-deposited films is formed the nanocrystalline cubic phase of manganese, the size of the CSR which L = 7,4 nm. There is a formation of solid solution nanocrystalline b-Mn phase in the original MnCr films (L ~ 7,5 nm). In the original state MnBiCr films is a mixture of rhombohedral Bi phase (L ~ 10,5 nm) and Mn cubic, which decays by heat treatment at ~ 703 K. Heat treatment of Mn and MnCr films at ~ 773 K leads to the formation of MnO oxide. For the MnCr films the activation energy (Ea) is ~ 3500-4800 K. In the MnBiCr films first phase transition (~ 573 K) is related with melting of Bi, the second, probably due to the collapse of the cubic Mn (~ 653 K, Ea ~ 7000 K). Analysis of the demagnetization curves of the MnBiCr films showed the manifestation of hard magnetic properties in a perpendicular field Hc~16′103 А/m.