Crystal and Magnetic Structure of MnAs0.92P0.08

Abstract

The chemical and magnetic structure of MnAs_0.92P_0.08 has been studied from 10° to 427°K using x‐ray and neutron diffraction. Below 440°K MnAs_0.92P_0.08 is orthorhombic (Pnma; c>a>b), and a refinement of the x‐ray data at lower temperatures showed that there was a continuous change of the Mn and As(P) atomic coordinates. The nuclear scattering, calculated using the x‐ray parameters, was subtracted from the measured neutron intensities. The resultant magnetic scattering indicated there must be both ferromagnetic and antiferromagnetic spin components. The orthorhombic magnetic space group, Pn′m′a, is consistent with both types of spin components and the observation of the 001 antiferromagnetic peak. A least‐squares fit at 200°K gave a ferromagnetic component of 2.0 μ_B along the c axis and an antiferromagnetic component of 1.6 μ_B along the a axis. Below 150°K further weak magnetic lines appear, indicating the onset of long period modulations. The Mn moment is consistent with a high spin rather than a low spin, in disagreement with published bulk magnetization data.