Fe掺杂La_(0.8)Sr_(0.2)Co_(1-x)Fe_xO_3磁性的研究  

THE STUDY OF MAGNETIC PROPERTIES IN Fe-doped La_(0.8)Sr_(0.2)Co_(1-x)Fe_xO_3 SYSTEM

作　　者：吴成国[1] 武文远[1] 龚艳春[1] 何苏红[1] 戴斌飞[1] 

机构地区：[1]解放军理工大学理学院,南京210007

出　　处：《低温物理学报》2008年第2期133-136,共4页Low Temperature Physical Letters

摘　　要：利用溶胶-凝胶法制备了一系列的La0.8Sr0.2Co1-xFexO3样品.通过研究在不同外加磁场下磁化强度和温度变化的关系发现,在较高的外场下La0.8Sr0.2Co1-xFexO3样品的磁性反转现象没有被观察到;在低场下La0.8Sr0.2Co1-xFexO3系统磁性反转现象被实现.这说明Fe的掺杂引起了La0.8Sr0.2Co1-xFexO3样品中铁磁和反铁磁之间的竞争,导致了La0.8Sr0.2Co1-xFexO3样品磁性反转;同时外加磁场的强弱影响了La0.8Sr0.2Co1-xFexO3系统磁性反转现象的发生,外加磁场增大使得在La0.8Sr0.2Co1-xFexO3样品中Co离子的自旋平行趋势更强,在铁磁和反铁磁之间的竞争中铁磁耦合占主导优势,因此在较高的外场下磁性反转现象没有被观察到.A series of La0.8Sr0.2Co1-xFexO3 samples are prepared by sol-gel method. Magnetization reversal of La0.8Sr0.2Co1-xFexO3 samples has not found in the high field but found in the low field with temperature dependence of magnetization. It is shown that Fe-doping induces the competition between ferromagnetism interaction （FM） of Co^3＋-O-Co^4＋ and superexchange antiferromagnetism interaction（AFM） of Co^3＋-O-Fe^3＋ and Co^4＋-O-Fe^3＋ in La0. 8 Sr0. 2 Co1-x FexO3 samples, which makes appearance of magnetization reversal. At the same time that the applied magnetic field affects the appearance of magnetization reversal, the more applied field leads to the more trends of Co ions spin parallel arrangement in La0.8Sr0.2Co1-xFexO3 samples, so the magnetization reversal is not observed in the more applied field because of the FM domination during the competition between FM and AFM.

关 键 词：铁磁和反铁磁之间竞争 磁性反转 溶胶-凝胶 自旋态 

分 类 号：O482.5[理学—固体物理]