缺氧La_(1-x)Na_xMnO_(2.825)陶瓷体系磁电性质(英文)

利用提高固相反应法烧结温度的方法制备了La1–xNaxMnO2.825(x=0.05,0.10,0.15,0.20)的缺氧陶瓷体系,测量了样品的X射线衍射谱、红外光谱、Raman光谱、磁化强度–温度曲线、电子自旋共振谱线、电阻率–温度曲线。结果表明:与La1–xNaxMnO3陶瓷相比,La1–xNaxMnO2.825陶瓷的磁化强度值变小,Curie温度下降,出现了相分离,原因是缺氧造成的Mn3+与Mn4+摩尔比的变化,以及样品中氧含量的不均匀性;缺氧陶瓷体系的电阻率升高,大部分样品表现为绝缘态,是氧空位引起的晶格作用、自旋作用与Mn3+与Mn4+的双交换作用共同竞争的结果。

MAGNETIC AND ELECTRICAL PROPERTIES OF La1-xNaxMnO2.825 CERAMICS WITH OXYGEN DEFICIENCY

La1-xNaxMnO2.825 (x=0.05, 0.10, 0.15, 0.20) ceramics with oxygen deficiency were prepared by the solid-state reaction method with high-temperature sintering. X-ray diffraction patterns, infrared spectra, Raman spectra, magnetization-temperature curves, electron spin resonance curves and resistivity-temperature curves of the samples were measured. It is found that the magnetization of La1-xNaxMnO2.825 ceramics is smaller than that of La1-xNaxMnO3 ceramics. The Curie temperature of La1-xNaxMnO2.825 ceramics decreases and the phase separation in the ceramics appears due to the oxygen deficiency and inhomogeneous distribution. The oxygen deficiency changes the mole ratio of Mn3+ to Mn4+. The resistivity of the ceramics increases and most samples exhibit insulator state which are the result from the competition between the lattice function and the spin function induced by the oxygen vacancy and the double-exchange function of Mn3+ to Mn4+.