Abstract:Tetragonal Sr3YCo4-xCuxO10.5+δ (x=0~1.0) polycrystals were prepared by solid-state reaction. The ordered phase transformation and structure of polycrystals were studied by thermogravimetric differential scanning calorimetry and X-ray diffraction. In the range of solid solubility (x=0~0.4), ordered peaks (103) and (215) are observed, indicating that tetragonal Sr3YCo4-xCuxO10.5+δ polycrystals are superstructure, which is due to the ordering transformation of oxygen absorption (δ) occurring above 1000℃ in synthesis. When x=0.6~1.0, monoclinic phase form at the grain boundary at 978℃, which destroys the order of Sr3YCo4-xCuxO10.5+δ polycrystal. When x=0~0.4, polycrystals are semiconductor transport characterization. With the increase of Cu doping, hole carriers concentration provided by Co4+ions improve, resistivity decreases obviously. Due to the solid solution of Cu, spin entropy increases, the cooperation of carrier concentration and spin entropy makes thermopower for x=0~0.2 polycrystals unchanged and decreases for x=0.4. Moreover, lattice distortion caused by Cu doping leads CO3+ ions transform from high spin state to high/low spin mixed state, magnetization and ferromagnetic transition temperature (Tc) decrease with Cu doping, and magnetic structure transforms from G-type antiferromagnetic to ferromagnetic. After double sinter, resistivity decreases obviously at 300K, and thermoelectric potential is twice more than that of single sinter, which may be the ordering degree of polycrystal increases after double sinter, and improve ferromagnetic ordered arrangement.