摘要
对钙钛矿结构锰酸盐巨磁电阻材料进行了阴离子掺杂的研究．Ｘ 射线衍射结果表明，Ｌａ２／３Ｃａ１／３Ｍ（Ｏ１－ ｘＦｘ）３化合物的空间群为Ｐｂｎｍ ，Ｚ＝４，Ｆ－ 离子占据８ｄ 位置， 随着ＣａＦ２ 掺入量的增加，晶格常数和晶胞体积呈递减趋势．ＣａＦ２ 的掺入使居里温度Ｔｃ 升高．分别在０ 磁场和Ｈ＝ ３９７７ｋＡ／ｍ 的外加磁场下进行阻温曲线的测量，各试样巨磁电阻比率ΔＲ／Ｒ０的峰值均在６７％ 以上，掺３ ％ （物质的量百分数）ＣａＦ２ 时ΔＲ／Ｒ０ 最大， 峰值达到７４％ ．
La 2/3 Ca 1/3 Mn(O 1- x , F x ) 3 bulk materials were prepared. X ray diffraction showed that the lattice parameters declined when more CaF 2 was added. Rietveld analysis indicated that the achieved specimens had orthorhombic perovskite structures with space group of Pbnm, Z=4, and F - occupying 8d positions. With the increase of CaF 2 , the paramagnetic to ferromagnetic transition temperature was improved. When 3% (amount of substance fraction) CaF 2 was doped, the magnetoresistance ΔR/R reached a maximum of 74%.
出处
《材料研究学报》
EI
CAS
CSCD
北大核心
1999年第5期519-522,共4页
Chinese Journal of Materials Research
关键词
巨磁电阻
峰形精修
晶体结构
钙钛矿结构
giant magnetoresistance, Rietveld analysis,La 2/3 Ca 1/3 MnO 3
