Magnetic Structure of MnAs and MnAs0·92P0·08

Abstract

The similarity of the ordered magnetic structures of orthorhombic MnAs (stable at high pressure) and orthorhombic MnAs_0.92P_0.08 has been confirmed using neutron diffraction. Below the magnetic ordering temperature, T_c, a canted spin structure is found for both materials. Neutron diffraction measurements from magnetically ordered and disordered temperature regions show that in these materials the Mn magnetic moment varies with the volume of the Mn atom. The variation of the magnitude of the Mn magnetic moment is explained using the relation between Pauling valence and magnetic moment introduced by Mori and Mitsui. The results are in disagreement with the currently accepted interpretation of the susceptibility data.