Search

In the present paper we report the structural and magnetoresistive properties of thecomposite series with; both the phases have been prepared using the chemical route method. With the BTO addition, the metal–insulator transition temperature () decreases till some optimum value of, after which it increases again. The inclusion of BTO causes an enhancement in magnetoresistance (MR) over a wide temperature range and it is maximum for the sample with. An increase in MR for the composite samples can be explained on the basis of the spin-dependent scattering and tunnelling of conducting electrons. [ABSTRACT FROM AUTHOR]

Highlights: [•] Characteristic properties of Mg0.95Co0.05TiO3–Ca0.8Sr0.2TiO3 composites have been studied. [•] The XRD data of the samples have been analyzed using Rietveld refinement method. [•] Theoretical permittivity has been calculated using different existing models. [•] The composite sample with x =0.07, sintered at 1275°C shows nearly zero τf . [ABSTRACT FROM AUTHOR]

Abstract: In this study we report the structural, electrical and magnetic properties of (1− x)La0.67Ca0.33MnO3 (LCMO)–(x)SrTiO3(STO) composites. For this series we have observed a minute change in ferromagnetic (FM)–paramagnetic (PM) transition temperature with STO addition in LCMO matrix; however a reasonable change is observed in metal–insulator transition temperature, along with the occurrence of percolation threshold for x =0.30 sample. Overall pattern for temperature dependence of resistivity for this series has been best-fitted using the formula 1/ρ =(1− f)/ρ PM +(f/ρ FM), whereρ PM and ρ FM are the resistivities of the PM and FM contents in the sample and f is the volume fraction of FM phase in the sample. Investigations on magnetoresistance (MR) using magnetic field up to 3T show enhancement of extrinsic MR in the composite samples which can be viewed in the light of spin polarized tunneling. [Copyright &y& Elsevier]