Abstract The family of Ba M F 4 with M of magnetic 3d transition metal ions is the typical multiferroic material. Pure phase solid solution of BaCoF 4 and BaNiF 4 with molar ratio of 1:1 (BaCo 0.5 Ni 0.5 F 4 ) is prepared by solid state reaction, which has been confirmed by X ray diffraction patterns. Field dependent magnetization measurements only show the linear curve with temperature down to 5 K, indicating the antiferromagnetic nature. Compared with BaCoF 4 and BaNiF 4 , no significant enhancement of magnetization is observed, indicating the absence of ferrimagnetism and the random distribution of Co and Ni ions. The low temperature magnetic anomalies are studied by zero field cooled (ZFC) and field cooled (FC) temperature dependent magnetization (M-T) measurements. A bifurcation between FC and ZFC M-T curves happens at 118 K, indicating the onset of 2-dimensional antiferromagnetism. The magnetization maximum at 87 K is attributed to the 2-dimensional antiferromagnetic clusters, followed by the drastic decrease of magnetization, which is due to the onset of 3-dimensional antiferromagnetism. A dip is observed in FC M-T curve at 40 K, which is attributed to the 3-dimensional antiferromagnetic clusters. A drastic increase of magnetization is observed at 9 K, which is due to the uncompensated isolated spins. Exchange bias is clearly observed, with blocking temperature of 90 K. The contribution from surface spin glass has been excluded by the AC magnetization measurements, and the mechanism has been explained by the exchange coupling between the two antiferromagnetic phases.

中文翻译：

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BaCo 0.5 Ni 0.5 F 4 的磁性能

摘要 具有磁性3d过渡金属离子的Ba MF 4 族是典型的多铁性材料。BaCoF 4 和BaNiF 4 摩尔比为1:1的纯相固溶体(BaCo 0.5 Ni 0.5 F 4 )是通过固相反应制备的，X射线衍射图证实了这一点。场相关磁化测量仅显示温度低至 5 K 的线性曲线，表明反铁磁性质。与BaCoF 4 和BaNiF 4 相比，没有观察到磁化强度的显着增强，表明没有亚铁磁性以及Co和Ni离子的随机分布。通过零场冷却 (ZFC) 和场冷却 (FC) 温度相关磁化 (MT) 测量来研究低温磁异常。FC 和 ZFC MT 曲线之间的分叉发生在 118 K，表明二维反铁磁性的开始。87 K 处的磁化最大值归因于 2 维反铁磁团簇，随后磁化强度急剧下降，这是由于 3 维反铁磁性的开始。在 40 K 的 FC MT 曲线中观察到下降，这归因于 3 维反铁磁团簇。在 9 K 处观察到磁化强度急剧增加，这是由于未补偿的孤立自旋。可以清楚地观察到交换偏置，阻挡温度为 90 K。交流磁化测量排除了表面自旋玻璃的贡献，并且通过两个反铁磁相之间的交换耦合解释了该机制。87 K 处的磁化最大值归因于 2 维反铁磁团簇，随后磁化强度急剧下降，这是由于 3 维反铁磁性的开始。在 40 K 的 FC MT 曲线中观察到下降，这归因于 3 维反铁磁团簇。在 9 K 处观察到磁化强度急剧增加，这是由于未补偿的孤立自旋。可以清楚地观察到交换偏置，阻挡温度为 90 K。交流磁化测量排除了表面自旋玻璃的贡献，并且通过两个反铁磁相之间的交换耦合解释了该机制。87 K 处的磁化最大值归因于 2 维反铁磁团簇，随后磁化强度急剧下降，这是由于 3 维反铁磁性的开始。在 40 K 的 FC MT 曲线中观察到下降，这归因于 3 维反铁磁团簇。在 9 K 处观察到磁化强度急剧增加，这是由于未补偿的孤立自旋。可以清楚地观察到交换偏置，阻挡温度为 90 K。交流磁化测量排除了表面自旋玻璃的贡献，并且通过两个反铁磁相之间的交换耦合解释了该机制。在 40 K 的 FC MT 曲线中观察到下降，这归因于 3 维反铁磁团簇。在 9 K 处观察到磁化强度急剧增加，这是由于未补偿的孤立自旋。可以清楚地观察到交换偏差，阻断温度为 90 K。交流磁化测量排除了表面自旋玻璃的贡献，并且通过两个反铁磁相之间的交换耦合解释了该机制。在 40 K 的 FC MT 曲线中观察到下降，这归因于 3 维反铁磁团簇。在 9 K 处观察到磁化强度急剧增加，这是由于未补偿的孤立自旋。可以清楚地观察到交换偏差，阻断温度为 90 K。交流磁化测量排除了表面自旋玻璃的贡献，并且通过两个反铁磁相之间的交换耦合解释了该机制。