Local cation order and ferrimagnetism in compositionally complex spinel ferrites
Local cation order and ferrimagnetism in compositionally complex spinel ferrites
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DOI：
10.1063/5.0123728
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发表时间：
2022-12
期刊：
影响因子：
6.1
通讯作者：
Xin Wang;B. Musicó;C. Kons;Peter C. Metz;V. Keppens;D. Gilbert;Yuanpeng Zhang;K. Page
中科院分区：
文献类型：
--
作者：
Xin Wang;B. Musicó;C. Kons;Peter C. Metz;V. Keppens;D. Gilbert;Yuanpeng Zhang;K. Page
我们探索了一类成分复杂的立方尖晶石铁氧体，包括镁、铁、钴、镍、铜、锰和锌离子的组合，系统地研究了平均和局域原子结构、化学短程有序、磁自旋组态和磁性。所有的成分都导致了具有非常相似的局域成键环境的亚铁磁性平均结构；然而，样品表现出不同程度的阳离子反转，因此，不同的表观体磁化度。此外，磁反转行为的一阶反转曲线分析表明，不同程度的磁有序和相互作用，包括潜在的局部受挫。最后，对自旋取向进行了逆蒙特卡罗模拟，证明了阳离子反转程度与自旋共线之间的关系。总的来说，这些观察结果与合成过程中的差异有关。这项工作为理解所报道的“高熵尖晶石”的磁性行为提供了一个框架，揭示了许多可能是成分复杂的氧化物，具有不同程度的化学短程有序-不符合社区为高熵或中熵化合物建立的标准。此外，这项工作强调了报告完整的样品处理历史和调查局部到远程原子排列的重要性，当评估高熵材料的潜在熵混合效应和假设的性质关联时。
We present an exploration of a family of compositionally complex cubic spinel ferrites featuring combinations of Mg, Fe, Co, Ni, Cu, Mn, and Zn cations, systematically investigating the average and local atomic structures, chemical short-range order, magnetic spin configurations, and magnetic properties. All compositions result in ferrimagnetic average structures with extremely similar local bonding environments; however, the samples display varying degrees of cation inversion and, therefore, differing apparent bulk magnetization. Additionally, first-order reversal curve analysis of the magnetic reversal behavior indicates varying degrees of magnetic ordering and interactions, including potentially local frustration. Finally, reverse Monte Carlo modeling of the spin orientation demonstrates a relationship between the degree of cation inversion and the spin collinearity. Collectively, these observations correlate with differences in synthesis procedures. This work provides a framework for understanding magnetic behavior reported for “high-entropy spinels,” revealing many are likely compositionally complex oxides with differing degrees of chemical short-range order—not meeting the community established criteria for high or medium entropy compounds. Moreover, this work highlights the importance of reporting complete sample processing histories and investigating local to long-range atomic arrangements when evaluating potential entropic mixing effects and assumed property correlations in high entropy materials.