采用固相反应法制备了La1-xNaxMnO3(x=0.05,0.15,0.33)多晶样品.通过测量XRD(X射线衍射)谱、R-T(电阻--温度)曲线、M-T(磁化强度--温度)曲线和ESR(电子自旋共振)曲线,研究了La位Na+离子替代对体系的电性和磁性的影响.实验结果表明:体系伴随绝缘体-金属相变出现顺磁--铁磁相变,随着La位Na+离子替代量的增加,样品的电阻值先减小后增大,磁化强度先增大后减小;随着La位Na+离子替代量的增加,居里温度单调升高;居里温度附近温区,顺磁相中存在着铁磁团簇,铁磁相中也存在顺磁成分.即出现了磁相分离;少量的Na+离子替代(x=0.05)样品,反铁磁与铁磁相共存,低温下表现为自旋倾斜玻瑞态特征,较高Na+离子替代样品的自旋倾斜玻璃态遭到破坏.体系磁电性质的变化来源于Na+离子替代引起的晶体晶格结构的变化、容忍因子t的变化和Mn3+/Mn4+离子比值的变化.
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