Role of t2g versus eg Interactions in the Physical Properties of A2OBO3 (A = Mn, Fe)

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• 作者：B. Rivas-Murias ; F. Rivadulla ; M. Sá ; nchez-Andú ; jar ; A. Castro-Couceiro ; M. A. Se&ntilde ; arí ; s-Rodrí ; guez ; J. Rivas
• 刊名：Chemistry of Materials
• 出版年：2006
• 出版时间：September 19, 2006
• 年：2006
• 卷：18
• 期：19
• 页码：4547 - 4552
• 全文大小：239K
• 年卷期：v.18,no.19(September 19, 2006)
• ISSN：1520-5002

文摘

From electron spin resonance (ESR), magnetization, and thermoelectric power on the isostructuralMn₂OBO₃ and Fe₂OBO₃, we have been able to establish important differences between the magneticproperties of these two compounds. These differences are rationalized on the basis of t_2g versus e_g electronicinteractions, orbital occupancy, and structure. For Mn₂OBO₃, we propose the possibility of fast electrontransfer between the Mn²⁺ and Mn³⁺ cations, in a similar way to the 3+/4+ Zener pairs in manganites.In the Fe₂OBO₃ system, our main findings are the observation of a magnetization reversal at low fieldand the observation of the spatially inhomogeneous short-range charge-order state that becomes trulylong-range only below the Néel temperature. The phase diagram of both compounds is reconsidered onthe basis of these results.