Abstract Magnetic behaviors of cobalt hydroxide fluoride, Co(OH)F2-x Fx (x = 1.09 and 1.26), which are consisted with nanorods of ∼5 μm length and diameter ∼100 nm, obtained by a facile hydrothermal method, have been researched with the variation of fluorine content as a result of the different amount of reactant NH4F addition. Magnetic coupling performance are characterized based on the observation and analysis of magnetic susceptibility, X-ray Absorption Fine Structure (XAFS) and specific heat. Co(OH)F2-x is found to undergo an antiferromagnetic transition at 40 K. The peak temperature (T) on the transition curves shifts to lower temperature according with the increased magnetic field (H) following the rule of H2/3∞ (-T) because of the surface spin-glass behavior. The paramagnetic susceptibility can be fitted with the modified Curie–Weiss law between 100 K and 320 K. The negative Curie-Weiss temperature indicates that the antiferromagnetic coupling becomes stronger with the fluorine content. In addition, at temperatures below 5 K, the magnetic reordering was observed as spin-glass. Exchange bias behavior in Co(OH)F2-x was found after field cooling process demonstrating an exotic surface magnetic behavior generated with high fluorine contents due to the deformation of CoO6 octahedral induced large spin-glass behavior.

中文翻译：

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纳米磁性随 Co(OH)F 中氟含量的变化

摘要 氢氧化氟化钴 Co(OH)F2-x Fx (x = 1.09 和 1.26) 的磁行为已被研究，该纳米棒由约 5 μm 长和约 100 nm 的纳米棒组成，通过简便的水热法获得。随着反应物NH4F添加量的不同，氟含量的变化。基于磁化率、X射线吸收精细结构（XAFS）和比热的观察和分析来表征磁耦合性能。发现 Co(OH)F2-x 在 40 K 发生反铁磁转变。转变曲线上的峰值温度 (T) 根据 H2/3∞ ( -T) 因为表面自旋玻璃行为。顺磁化率可以在 100 K 和 320 K 之间符合修正的居里-魏斯定律。负居里-魏斯温度表明反铁磁耦合随着氟含量的增加而变得更强。此外，在低于 5 K 的温度下，观察到磁性重排为自旋玻璃。在场冷却过程后发现 Co(OH)F2-x 中的交换偏置行为，表明由于 CoO6 八面体变形引起的大自旋玻璃行为，高氟含量产生了奇异的表面磁性行为。