Investigation of structural, magnetic and electric transport properties of half-doped chromium manganites La0.3R0.2Sr0.5Mn0.5Cr0.5O3 (R=La, Nd, Sm, and Gd)

The effect of smaller rare-earth substitution in the La site of La0.5Sr0.5Mn0.5Cr0.5O3 has been investigated to elucidate how the properties of this material change with La doping. La0.3R0.2Sr0.5Mn0.5Cr0.5O3 (R=La, Nd, Sm, and Gd) compounds have been studied by X-ray diffraction and magnetic and transport measurements. All the samples were determined to be single phase and crystallized in an orthorhombic structure. Magnetic measurements showed that doping of smaller rare-earth ion for La decreases both Curie temperature (TC) and Weiss constant (Θ). Except R=La, all the phases follow Curie–Weiss law in the high temperature region. All the samples are semiconducting and the transport properties are dominated by the adiabatic small polaron hopping mechanism.