Electronic State of High Spin MnAs

The electronic state of high spin MnAs was investigated by using the polarized neutron technique. The experimental results are summarized as follows: i) By analyzing the asphericity of the magnetic form factor with the free ion model, the numbers of electrons in the atomic levels are determined to be (1.0↑+0.3↓, 2.0↑, 0.7↑) for (ψ x 0 , ψ x ± , ψ u ± ) atomic levels, respectively. Therefore, Mn atoms are in the 3d 4 electronic state in MnAs. ii) This electron configuration is convenient to explain the observed metallic conductivity. iii) The spin density distribution shows the characteristics of the above mentioned electron configuration and the strong covalency with the anion As. iv) Spherical part of the magnetic form factor agrees with the calculated one for Mn + , not for Mn 3+ . But this does not imply the Mn atom is in the Mn + state.