Pr_(0.4)Ca_(0.6)Mn_(1-x)Cr_xO_3的磁性质及电荷有序相  

Magnetic Property and Charge Ordering Phase in Pr_(0.4)Ca_(0.6)Mn_(1-x)Cr_xO_3

作　　者：刘鹏[1,2] 王桂英[1,2] 毛强[1,2] 李莉 叶吾梅[1,2] 彭振生[1] 

机构地区：[1]自旋电子与纳米材料安徽省重点实验室,安徽宿州234000 [2]宿州学院机械与电子工程学院,安徽宿州234000

出　　处：《稀土》2015年第2期49-54,共6页Chinese Rare Earths

基　　金：国家自然科学基金重点项目(19934003);安徽省教育厅自然科学研究重点项目(KJ2013A245;KJ2012Z404);自旋电子与纳米材料安徽省重点实验室开放课题(2014YKF49;2012YKF07;2014YKF48)

摘　　要：用固相反应法制备了Pr0.4Ca0.6Mn1-xCrxO3(x=0,0.04,0.06,0.08,0.10,0.12),通过X射线衍射(XRD)图谱,磁化强度-温度(M-T)曲线、电子自旋共振(ESR)图谱,并用ESR作出归—化强度-温度(I/I300—T)曲线、谱线宽度-温度(△Bpp-T)曲线,研究Cr3+替代Mn3+对Pr0.4Ca0.6MnO3的磁性质及电荷有序相的影响。结果表明,母体样品Pr0.4Ca0.6MnO3的电荷有序转变温度Tco=267 K,205K^62 K温区是长程反铁磁序,50 K以下在反铁磁背景下出现少量铁磁成分;Cr替代量x=0.06时,电荷有序相已基本被破坏,随温度降低材料从顺磁向反铁磁转变,同时在反铁磁背底下存在铁成分;Cr替代量达到x=0.10时,电荷有序相完全被破坏,250 K以下是反铁磁与铁磁混合相,铁磁成分增多。用有磁性的且与Mn4+有相同电子结构(t32ge0g)的Cr3+替代Mn3+破坏电荷有序相的机制是:Cr3+替代Mn3+引起自旋序的改变从而引起电荷序的破坏,说明在CE型反铁磁体系中,自旋序与电荷序之间存在强耦合相互作用。Pr0.4Ca0.6Mn1-xCrxO3 （x = 0. 00,0. 04,0. 06,0. 08,0. 10,0. 12） were prepared by the solid ,- state reaction method. The influences of Cr^3＋ substitution for Mn^3 ＋ on magnetic property and charge ordering phase of Pr0.4 Ca0.6 MnO3 were studied through X- ray diffraction （XRD） patterns, magnetization -temperature （M -T） curves, electron spin resonance （ESR） patterns, normalized intensity - temperature （I/I300 - T） curves and peak- peak band width -temperature （△ Bpp- T） curves according to ESR. The results indicate that, for the original material Pr0.4 Ca0.6 MnO3, charge ordering transition temperature Too is equal to 267 K, long - range antiferromagnetic order exists in the temperature range 205 K - 62 K, and a little ferromagnetic component appears in the antiferromagnetic background below 50 K; for the sample with x = 0. 06, charge ordering phase has basically been destroyed, paramagnetism - antiferromagnetism transition occurs with tempera- ture decreasing, and ferromagnetic component exists in the antiferromagnetic background; for the sample with x = 0. 10, charge ordering phase has completely been destroyed, antiferromagnetic and ferromagnetic mixed phase exists below 250 K, and ferromagnetic component increases. Charge ordering phase has been destroyed because of the substitution of magnetic Cr^3＋ with the same electronic structure （t2g^3e0^0） as Mn^4＋ for Mn^3＋, the mechanism is that Cr^3＋ substitution for Mn^3 ＋ causes the spin order to change and then causes the charge order to be destroyed, and this indicates that strong coupling interaction between the spin order and the charge order exists in CE - type antiferromagnetie system.

关 键 词：电荷有序相 磁性质 Cr^3+替代Mn^3+ Pr0.4Ca0.6MnO3 

分 类 号：TM273[一般工业技术—材料科学与工程]