Abstract The aim of this work is to study the La 2 FeMnO 6 double perovskite system from an experimental point of view. The nanoparticles were prepared through the ionic coordination reaction method and have a mean particle size of 36 nm, as determined by MEV analysis. The crystal structure is monoclinic with P21/n space group. The 57 Fe Mossbauer spectroscopy (MS) study reveals that Fe ions species have a dominant magnetic spectra at temperatures smaller than 90 K, and above 180 K the spectra are dominated by a paramagnetic component. The magnetization versus temperature (MxT) measurement showed a fast increase of magnetization at temperatures below 130 K and seems to be related to the Fe moments. The M −1 x T data follows a linear trend for T > 591 K indicating a magnetic transition at this temperature. The MS and the magnetic data reveal that for T > 180 K the ferromagnetic signal is mainly due to Mn 3+ -O-Mn +4 clusters. Studies on AC susceptibility as a function of frequency suggested a cluster spin glass transition at 98.9 K, and the field cooling MxH loops depicted an exchange bias effect below 20 K. Both results indicate the complexity of this system making it of great interest in basic research and practical applications.

中文翻译：

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La2FeMnO6 纳米颗粒中的交换偏置和自旋玻璃

摘要 这项工作的目的是从实验的角度研究La 2 FeMnO 6 双钙钛矿系统。纳米粒子通过离子配位反应方法制备，平均粒径为 36 nm，由 MEV 分析确定。晶体结构为P21/n空间群的单斜晶系。57 Fe Mossbauer 光谱 (MS) 研究表明，Fe 离子种类在低于 90 K 的温度下具有主要的磁谱，而在 180 K 以上的谱则以顺磁成分为主。磁化强度与温度 (MxT) 测量结果表明，在低于 130 K 的温度下磁化强度快速增加，并且似乎与 Fe 矩有关。M -1 x T 数据遵循 T > 591 K 的线性趋势，表明在该温度下发生磁转变。MS 和磁性数据表明，对于 T > 180 K，铁磁信号主要是由于 Mn 3+ -O-Mn +4 簇。AC 磁化率作为频率函数的研究表明，在 98.9 K 处发生簇自旋玻璃化转变，场冷却 MxH 回路描绘了低于 20 K 的交换偏置效应。这两个结果都表明该系统的复杂性使其对基础研究产生了极大的兴趣和实际应用。