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烧结Sr1-xCaxRuO3系列的结构与磁性
STRUCTURE AND MAGNETIC PROPERTIES OF SINTERED Sr1-xCaxRuO3 SERIES
【摘要】 固相反应法制备了Sr1-xCaxRuO3系列,X射线衍射确定样品的相结构为正交畸变钙钛矿结构.随Ca替代量x的增加,晶格常数a基本保持不变,而b和c随之减小,晶格畸变更加明显.物理性质测量系统(PPMS)测量了样品的交流磁化率,零场冷却和加场冷却磁化强度.Curie-Weiss定律确定了样品的顺磁Curie温度Tp.结果表明,随x的增加,Tp减小.当x<0.6时Tp大于零;当x>0.6时Tp小于零.利用交流磁化率随温度变化的关系确定样品的铁磁Curie温度Tc,随x的增加Tc减小.当x=0.8时,Tc降至4K;而当x=1.0时,即使温度降到1.7K,也未出现磁有序.样品磁性随Ca替代量x的变化是其结构变化的直接结果.
【Abstract】 Sr1-xCaxRuO3 series was prepared by a solid state reaction method and characterized by X-ray diffraction, which showed that the structure is orthorhombically distorted perovskite with space group of Pbnm. The lattice parameter a keeps almost constant with the Ca content x increasing, but the lattice parameters b and c decrease with x increasing. The orthorhombical distortion becomes larger with more substitution of calcium. The paramagnetic Curie temperature Tp was obtained by Curie-Weiss law, and Tp decreases with x increasing. When x <0.6, Tp is positive, but when x >0.6, Tp is negative. The ferromagnetic Curie temperature TC was obtained by the peak of susceptibility against temperature, and TC decreases with x increasing. When a;=0.8, TC is down to 4 K. When x=1.0, no magnetic ordered phase was observed even though the temperature is down to 1.7 K. The differences in magnetic properties between SrRuO3 and CaRuO3 are due to their crystalline structures.
【Key words】 FC magnetization; ZFC magnetization; AC susceptibility; ferromagnet;
- 【文献出处】 金属学报 ,Acta Metallrugica Sinica , 编辑部邮箱 ,2002年07期
- 【分类号】TM271
- 【被引频次】1
- 【下载频次】66