Crystal structure, magnetic properties and conductivity mechanisms of La0.7Ca0.3Mn0.5Fe0.5O3

ABSTRACTLa0.7Ca0.3Mn0.5Fe0.5O3 (LCMFO) ceramic samples were prepared by conventional solid-state reaction. X-Ray diffraction investigations show that samples have orthorhombic space group Pnma (a = 5.447(2) Ǻ, b = 7.709(3) Ǻ, c = 5.467(3) Ǻ). During the neutron powder diffraction measurements of LCMFO in the temperature range of 10 ÷ 300 K the antiferromagnetic long-range ordering of G-type was seen. It has been established that 50% substitution of Mn/Fe leads to a complete suppression of the ferromagnetism in LCMFO samples. Investigations of temperature dependence of the magnetization, M(T), suggests the frustration of magnetic ground state and the existence of a spin-glass or a cluster-glass phase below the magnetic transition temperature close to 350 K. The temperature dependences of conductivity for La0.7Ca0.3Mn0.5Fe0.5O3 sample investigated in magnetic fields B = 0 and 1 T. According to the research, the mechanisms of hopping conductivity were established. Micro parameters in density of localized sta...