Abstract In this work we present an experimental and theoretical study of the magnetic and hyperfine properties of (Fe, Co) co-doped rutile SnO2 (FexCoySn1-x-yO2). Ab initio calculations were performed in the framework of the Density Functional Theory (DFT) using the full-potential linearized augmented plane wave (FP-LAPW) method. The effect of the oxygen vacancies on the magnetic and hyperfine properties and on the magnetic alignment of Fe and Co impurities was studied considering different vacancy concentrations and distributions in the host. Our calculations predicted that the Fe and Co impurities tend to be located as close as possible and favors the generation of oxygen vacancies, forming a pair of magnetic impurities sharing oxygen vacancies with an antiparallel spin alignment, giving rise to a ferrimagnetic entity. Ab initio predictions were compared with experimental results: magnetization curves obtained by vibrating sample magnetometry (VSM) at room temperature and Mossbauer spectroscopy (MS) studies obtained for SnO2 samples doped with 1.0% of Fe and co-doped with Co concentrations ranging from 0.0 to 0.5%, grown by sol-gel and thermal decomposition method. The comparison enabled us to identify the observed hyperfine interactions in MS experiments and characterize the local structure around the Fe atoms unambiguously. Finally, based on our theoretical results for the lowest energy Fe–Fe, Fe–Co and Co–Co magnetic configurations we can understand and reproduce the experimental behavior obtained by VSM measurements of the saturation magnetization (MS) (similar to the magnetic moment per magnetic atom) as a function of the Co concentration.

中文翻译：

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杂质和氧空位在 Fe Co Sn1--O2 磁响应中的作用。实验和从头研究

摘要 在这项工作中，我们对 (Fe, Co) 共掺杂的金红石 SnO2 (FexCoySn1-x-yO2) 的磁性和超精细特性进行了实验和理论研究。Ab initio 计算是在密度泛函理论 (DFT) 的框架内使用全电位线性化增强平面波 (FP-LAPW) 方法进行的。考虑到主体中不同的空位浓度和分布，研究了氧空位对磁性和超精细性质以及 Fe 和 Co 杂质的磁性排列的影响。我们的计算预测，Fe 和 Co 杂质往往位于尽可能靠近的位置，并有利于氧空位的产生，形成一对磁性杂质，以反平行自旋排列共享氧空位，从而产生亚铁磁体。将 Ab initio 预测与实验结果进行比较：在室温下通过振动样品磁力计 (VSM) 获得的磁化曲线和为掺杂 1.0% Fe 和共掺杂 Co 浓度范围为 0.0 至0.5%，通过溶胶-凝胶和热分解法生长。该比较使我们能够识别 MS 实验中观察到的超精细相互作用，并明确表征 Fe 原子周围的局部结构。最后，基于我们对最低能量 Fe-Fe、Fe-Co 和 Co-Co 磁构型的理论结果，我们可以理解并重现通过 VSM 测量饱和磁化强度 (MS)（类似于每个磁矩的磁矩）获得的实验行为。磁性原子）作为 Co 浓度的函数。