Crystal and Electronic Structure and Magnetic Properties of Divalent Europium Perovskite Oxides EuMO3 (M = Ti, Zr, and Hf): Experimental and First-Principles Approaches

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• 作者：Hirofumi Akamatsu ; Koji Fujita ; Hiroyuki Hayashi ; Takahiro Kawamoto ; Yu Kumagai ; Yanhua Zong ; Koji Iwata ; Fumiyasu Oba ; Isao Tanaka ; Katsuhisa Tanaka
• 刊名：Inorganic Chemistry
• 出版年：2012
• 出版时间：April 16, 2012
• 年：2012
• 卷：51
• 期：8
• 页码：4560-4567
• 全文大小：444K
• 年卷期：v.51,no.8(April 16, 2012)
• ISSN：1520-510X

文摘

A comparative study of the crystal and electronic structure and magnetism of divalent europium perovskite oxides EuMO₃ (M = Ti, Zr, and Hf) has been performed on the basis of both experimental and theoretical approaches playing complementary roles. The compounds were synthesized via solid-state reactions. EuZrO₃ and EuHfO₃ have an orthorhombic structure with a space group Pbnm at room temperature contrary to EuTiO₃, which is cubic at room temperature. The optical band gaps of EuZrO₃ and EuHfO₃ are found to be about 2.4 and 2.7 eV, respectively, much larger than that of EuTiO₃ (0.8 eV). On the other hand, the present compounds exhibit similar magnetic properties characterized by paramagnetic-antiferromagnetic transitions at around 5 K, spin flop at moderate magnetic fields lower than 1 T, and the antiferromagnetic nearest-neighbor and ferromagnetic next-nearest-neighbor exchange interactions. First-principles calculations based on a hybrid Hartree鈥揊ock density functional approach yield lattice constants, band gaps, and magnetic interactions in good agreement with those obtained experimentally. The band gap excitations are assigned to electronic transitions from the Eu 4f to Mnd states for EuMO₃ (M = Ti, Zr, and Hf and n = 3, 4, and 5, respectively).