摘要
用固相反应法制备La0.4Ca0.6Mn1-xGaxO3(x=0,0.08,0.10,0.12,0.15)系列多晶样品。通过X射线衍射(XRD)图谱、电阻率-温度(ρ-T)曲线、磁化强度-温度(M-T)曲线和电子自旋共振(ESR)图谱,研究Ga3+替代Mn3+对La0.4Ca0.6Mn1-xGaxO3体系电荷有序相的影响。结果表明,当Ga掺杂量高达15%时电荷有序相仍然没有被破坏。这是因为Ga3+是非磁性离子,而La0.4Ca0.6MnO3是CE型反铁磁电荷有序相结构,Ga3+替代Mn3+只是仅仅起到把体系中的长程自旋序破坏为短程自旋序的作用,同时随Ga替代量增大,Mn3+与Mn4+的比远离双交换的最佳摩尔配比(Mn3+∶Mn4+=2∶1),不利于双交换,因而非磁性的Ga3+替代Mn3+难以破坏La0.4Ca0.6MnO3的电荷有序相。
Polycrystalline samples La0.4Ca0.6Mn1-xGaxO3（x =0, 0.08, 0.10, 0. 12, 0.15） were prepared by the solid-state reaction method. The influence of Ga^3＋ substitution for Mn3 ＋ on charge ordering phase of La0.4 Ca0.6 Mn1-x G8xO3 system was studied through the measurements of X-ray diffraction （XRD） patterns, resistivity-temperature （p-T） curves, （M- T） curves and electron spin resonance （ESR） patterns. The results indicated that the charge ordering phase was still not destroyed when the Ga doping amount was as high as 15%. This was because that Ga^3＋ was a nonmagnetic ion, La0.4Ca0.6MnO3 was in the structure of CE-type antfferromagnetic charge ordering phase. Ga^3＋ substitution for Mn^3＋ only changed long-range spin order of the system to short-range spin order. Meanwhile, with the increase of Ga substitution amount, the molar ratio of Mn^3＋ and Mn^4＋ was far away from the best ratio （ Mn^3＋ ： Mn^4＋ = 2 ： 1 ）, which was not beneficial to double exchange. Therefore, nonmagnetic Ga^3＋ substitution for Mn^3＋ could not destroy the charge ordering phase of La0.4Ca0.6MnO3.
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2014年第4期635-640,共6页
Chinese Journal of Rare Metals
基金
国家自然科学基金重点项目(19934003)
安徽省自然科学基金项目(1308085MA11)
安徽省教育厅自然科学研究重点项目(KJ2013A245,KJ2011A259,KJ2012Z404)
自旋电子与纳米材料安徽省重点实验室培育基地开放课题(2012YKF09,2012YKF10,2012YKF08)资助
