MAGNETIC AND CRYSTALLOGRAPHIC STUDIES OF COMPOUND MNAS0.9P0.1

Crystallographic and magnetic properties of the compound MnAs0.9P0.1 are studied in the temperature range from 4.2 to 660°K. X-ray diffraction studies reveal this compound deforms at 440°K with decreasing temperature from hexagonal B81 into orthorhombic B31 structure, as pointed out by Goodenough et al. Degree of the orthorhombic deformation δ (shown in the text) in this case is first found to increase gradually from 440°K with lowering temperature, then rises steeply, reaching a δ-value of 2%, and remains constant with further fall of temperature. The magnetic measurements at low temperature reveal that the present compound is metamagnetic with saturation magnetization of 69 e.m.u./g at 4.2°K, while it shows a ferromagnetic behavior above Liquid air temperature. Based on the present result, it can be shown that the manganese ion in this compound below Curie temperature is in a low spin state with spin value S=0.8. It is also shown that the manganese ions is in a high spin state for vanishing δ, in a low spin state for δ>0.8% and in a transitional spin state for 0.8%>δ>0%. © 1968, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.