Electrical Property of Cubic Perovskite-Type Sr(Mn_1-xNb_x)O₃ in Mn-Rich Region

Abstract

Cubic perovskite-type Sr(Mn_1-xNb_x)O₃ (0.03≤x≤0.2) was synthesized by a standard ceramic technique. The cell constant increased linearly with increasing x. Sr(Mn_0.97Nb_0.03)O₃ (x=0.03) exhibited a metal-insulator transition at ca. 390 K, whereas Sr(Mn_1-xNb_x)O₃ (0.05≤x≤0.2) was an n-type semiconductor in a temperature range of 80-773 K. From the magnetic measurement, it is obvious that the metal-insulator transition was caused by the change in the spin state of the Mn³⁺ ion. The Seebeck coefficient of Sr(Mn_1-xNb_x)O₃ (0.03≤x≤0.2) was negative and showed no significant difference in the composition.