The conductivity of magnetically-ordered MnAs1–xPx-compounds

The conductivity and the derivative of the conductivity d[sgrave]/dT of magnetically-ordered MnAs1–x P x single crystals have been measured in the temperature range from 100 to 420 K and for compositions between x=0 and x=0.15 and very near the critical composition x c=0·03. Susceptibility data for these compounds were used to identify the influence of magnetic order on the electron mobility. The analysis of the conductivity yields evidence of the split d bands which have been suggested for these compounds. These d bands shift and split with increasing orthorhombic distortion. Taking the highest d subband (e) as conduction band, the width of the lower one (a 1 T) is estimated as W ≈ 0·15 eV in the hexagonal phase and W ≈ 0·09 eV in the orthorhombic phase. Also, a significant increase in the resistivity at the Néel point T N of MnAs0·97P0·03 can be explained by a splitting of the second d subband due to antiferromagnetic coupling.