Design and Crystal Growth of Magnetic Double Perovskite Iridates: Ln2MIrO6 (Ln = La, Pr, Nd, Sm-Gd; M = Mg, Ni)

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• 作者：Timothy Ferreira ; Gregory Morrison ; Jeongho Yeon ; Hans-Conrad zur Loye
• 刊名：Crystal Growth & Design
• 出版年：2016
• 出版时间：May 4, 2016
• 年：2016
• 卷：16
• 期：5
• 页码：2795-2803
• 全文大小：500K
• 年卷期：0
• ISSN：1528-7505

文摘

A series of monoclinic distorted double perovskites of the general formula Ln₂MIrO₆ (Ln = La, Pr, Nd, Sm–Gd; M = Mg, Ni) were grown as highly faceted single crystals from a potassium hydroxide flux. The structural distortions and the magnetic interactions in A₂BB′O₆ double perovskites can be “designed” via a judicious choice of A, B, and B′ cation sizes and by selecting magnetic or nonmagnetic ions to occupy the A, B, and/or B′ sites. A study of the relationship between the number of magnetic ions, the degree of monoclinic distortion, and the resulting magnetic interactions was conducted. Magnetic susceptibility and field dependent magnetization measurements were performed for all synthesized compounds. It was determined that smaller A-site lanthanide cations cause more pronounced monoclinic distortions, resulting in smaller M–O–Ir (M = Mg, Ni) bond angles that correlate with higher magnetic ordering temperatures. The magnetic susceptibility and field dependent magnetization data were both consistent with canted antiferromagnetism for most titled compositions, indicating a possible trend of increased spin canting, and thus increased ferromagnetic-like interactions, as a function of smaller lanthanide A site cation size.