Structural, electrical and magnetic properties of nickel manganite obtained by a complex polymerization method

Structural, electrical and magnetic properties of nickel manganite ceramics obtained by sintering fine powders prepared by a complex polymerization method are given in this work. The phase composition of the synthesized material was examined by x-ray powder diffraction (XRPD). Field-emission scanning electron microscopy (FE-SEM) was used to analyze the obtained powder morphology. Scanning electron microscopy (SEM) was used to analyze the microstructure of sintered ceramics. The activation energy of conduction Ea and the coefficient of temperature sensitivity B25/100 were calculated from direct current (DC) resistivity measurements. The magnetization dependence of temperature M(T) and alternating current (AC) susceptibility data obtained from SQUID measurements clearly demonstrate that quadruple magnetic phase transitions can be readily detected at TM1~115 K, TM2~105 K, TM3~38 K and TM4~7 K. These findings suggest a novel magnetic transition for nickel manganite at low temperature TM4.