文章基本信息

标题：Unusual ferromagnetism enhancement in ferromagnetically optimal manganite La_0.7−_yCa_0.3+_yMn₁₋_yRu_yO₃ (0≤y<0.3): the role of Mn-Ru t_2g super-exchange
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作者：M. F. Liu ; Z. Z. Du ; Y. L. Xie 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2015
卷号：5
DOI：10.1038/srep09922
出版社：Springer Nature
摘要：The e_g -orbital double-exchange mechanism as the core of physics of colossal magnetoresistance (CMR) manganites is well known, which usually covers up the role of super-exchange at the t_2g -orbitals. The role of the double-exchange mechanism is maximized in La_0.7Ca_0.3MnO₃, leading to the concurrent metal-insulator transition and ferromagnetic transition as well as CMR effect. In this work, by a set of synchronous Ru-substitution and Ca-substitution experiments on La_{0.7– y}Ca_{0.3+ y}Mn_{1– y}Ru _y O₃, we demonstrate that the optimal ferromagnetism in La_0.7Ca_0.3MnO₃ can be further enhanced. It is also found that the metal-insulator transition and magnetic transition can be separately modulated. By well-designed experimental schemes with which the Mn³⁺-Mn⁴⁺ double-exchange is damaged as weakly as possible, it is revealed that this ferromagnetism enhancement is attributed to the Mn-Ru t_2g ferromagnetic super-exchange. The present work allows a platform on which the electro-transport and magnetism of rare-earth manganites can be controlled by means of the t_2g -orbital physics of strongly correlated transition metal oxides.