室温铁磁性四方超结构Sr3ErCo4O10.5+δ多晶的制备及电磁输运性能.

Room temperature ferromagnetic tetragonal superstructure Sr3ErCo4O10.5+δ polycrystals were prepared by solid-state reaction method.XRD and SEM were used to characterize the structure and cross-sectional morphology of polycrystals prepared at 7 different sintering temperatures between 1025 and 1200℃. At 1 025 ℃,the polycrystalline crystallization of Sr3ErCo4O10.5 was completed and appeared heterogeneous Er2O3. With the increase of sintering temperature, the (103), (215) peak intensities of superstructure increased, the impurity phase decreased gradually; the Sr3ErCo4O10.5+δ grain grew, the porosities decreased and the lattice integrity improved.At 1160℃,the peak intensities of superstructure were the highest, the impurity phase disappeared completely, and the degree of ordering was the best.With the increase of sintering temperature, the peak intensities of superstructure decreased, the degree of ordering weakened, and Er2O3 appeared on the particle surface. TG-DSC showed that the polycrystal absorbed oxygen (δ) at 1 025-1200℃ and gradually completed the ordering. Iodine titration further confirmed that the stoichiometric ratio of polycrystal oxidation increased with the increase of sintering temperature.Polycrystal was prepared at 1160℃,which resistivity of 300 K was 0.09 Ω· cm, and the ferromagnetic-paramagnetic transition temperature (Tc) of polycrystal was 332 K, and the M-H curve further proved that the polycrystal was ferromagnetic at room temperature and underwent paramagnetic-ferromagnetic transformation at 332 K. [ABSTRACT FROM AUTHOR]