Magnetic properties of MnFeP0.5As0.5-xGex

The structural and magnetic properties of the quasi-ternary MnFeP0.5As0.5-xGex compounds with x = 0, 0.06, 0.1, 0.2, 0.3, 0.4, and 0.5 are investigated by means of X-ray diffraction, differential scanning calorimetry and magnetization measurements. For the whole substitution range of Ge for As, the compounds retain the hexagonal Fe2P-type of structure. With increasing Ge concentration, the Curie temperature shifts from room temperature to 570 K. The magnetic-ordering transition becomes of second order and, as a consequence, the magnetic-entropy change decreases with increasing Ge content. The observed evolution of magnetism in these compounds is discussed based on the substitution-induced variation of the interatomic distances.