Structural, transport and magnetic properties of

The double perovskite, Sr2RuTiO6 has been studied by X-ray powder diffraction, magnetizations and magnetoresistance techniques. Rietveld analysis of the X-ray diffraction shows that the sample crystallizes in tetragonal structure with space group I 4 / m c m and there is no indication of long range Ru/Ti cation ordering. The magnetic studies point towards the existence of magnetic polarons in the paramagnetic state with a weak ferromagnetic transition at 145 K. The temperature dependent magnetoresistance studies reveal an unusual cross over from positive to negative magnetoresistance at low temperature (∼15 K). The complex magnetotransport properties of Sr2RuTiO6 arise from the competing ferromagnetic and antiferromagnetic superexchange interactions between Ru ions via Ti/O ions, initiated by the B-site cation disorder.