STRUCTURE, MAGNETIC-SUSCEPTIBILITY AND HEAT-CAPACITY OF SCMNO3

Structure refinement of the room temperature X-ray powder diffraction data of ScMnO3 was carried out by Rietveld technique, based on the most probable space group P6(3)cm. The manganese and scandium atoms are surrounded by five and seven oxygen atoms respectively. Three manganese atoms make three kinds of triangles (two regular and an isosceles). A weak ferromagnetic behaviour with small hysteresis was observed below 130 K on the magnetization curve and ScMnO3 becomes completely paramagnetic above it. The heat capacity of ScMnO3 was measured from 77 to 800 K by two types of calorimeters (a.c. calorimeter and differential scanning calorimeter). At 129 K a lambda-type anomaly was seen in the heat capacity curve which corresponds to the magnetic transition. The enthalpy change and entropy change that accompanied the magnetic transition were 178 J mol(-1) and 1.40 J mol(-1) K-1 respectively. The baseline of the heat capacity from 150 to 250 K yields a Debye temperature of 615 K.