Perovskite Ruthenium Oxide Sr <sub> 1-x </ Sub> Ca <sub> The X </ Sub> Of Ruo <sub> 3 </ Sub> (0 ¡Ü X ¡Ü 1) Series Of Samples Of The Magnetic Properties And Transport Properties

Polycrystalline samples of Sr_1-xCa_xRuO₃ (x=0.0, 0.2, 0.4, 0.6, 0.8, 1.0) and SrRuO₃ have been made by a chemical co-precipitation method, and a solid state reaction method respectively. We have studied their structure, grain sizes, magnetic properties, transport properties. XRD results show that the samples are single phase of perovskite-type oxides. The grain sizes of the samples are observed by SEM. The samples magnetic properties are measured on a vibrating sample magnetometer (VSM) and a Quantum Design PPMS 9 system. The samples transport properties are measured on a Quantum Design PPMS 9 system and a Maglab Exa Measurement System. The main experimental results are as follows.1. Results of series samples Sr_1-xCa_xRuO₃ prepared by a chemical co-precipitation method.(1) The studies on samples' structure show that Sr_1-xCa_xRuO₃ series sintered at 1473 K, 1673 K are orthorhombically distorted perovskite.(2) The grain sizes of Sr_1-xCa_xRuO₃ observed by SEM images are 150 to 300 nm.(3) The SrRuO₃ samples' Curie temperatures are all 161 K, which are sintered at 1273 K, 1473 K, 1673 K respectively.(4) The temperature dependence of resistivities of Sr_1-xCa_xRuO₃ serial samples which are prepared by a chemical co-precipitationmethod show obvious semiconductor behavior. With the increase of Ca substitution, resistivity increase, resistivity reach it's maximum magnitude when x=0.8. The magneto-resistor is negative at low temperature, with the increase of temperature, magneto-resistor decrease, and decrease to zero near Curie temperature.2. Results of sample SrRuO3 prepared by a solid state reaction method.(1) The X-ray diffraction pattern indicates that the SrRuC>3 sample has the orthorhombic perovskite structure. The grain size of sample observed directly by SEM images is about 1.8//m.(2) The structure distortion of SrRuC>3 sample which is prepared by a solid state reaction method is different from other literatures' report prepared by the same method, and then induces the Curie temperature deceasing to 149 K, calculated from XRD experimental data.(4) With the temperature increase, the resistivity of SrRu(>3 sample increases, and appears metallic behavior. The magneto-resistor of SrRuCh sample is negative, and reach it's maximum magnitude near Curie temperature, about 1 % .