Abstract Magnetic resonance characteristics of mixed chalcospinel nanocrystals CuCr2SxSe4−x (x = 0 and 2) and CoxCu1−xCr2S4 (x = 0.1 and 0.2) have been investigated. It has been established based on TEM, SEM and resonance data that all the samples contain both blocks with sizes from 1 to 50 m of compacted nanosized crystallites and individual nanoparticles with sizes from 10 to 30 nm. The studies provide evidence of strong interparticle interaction in all the samples leading to high values of the blocking temperature. Magnetic dipolar field arise in the boundary regions of interacting adjacent nanocrystals below the blocking temperature. This results in inhomogeneous broadening of the magnetic resonance spectrum along with appearance of additional absorption lines. With increase in magnetic anisotropy at low temperatures, a shift of the resonance field along with line broadening are observed for all the studied compounds due to freezing of the moments in the nanoparticles, both in the individual and compacted ones. A gapped characteristic of the resonance spectrum is established below the freezing temperature Tfr, with the energy gap defined by the averaged magnetic anisotropy . Anionic substitution of sulfur by selenium results in a decrease in the magnetic anisotropy. In contrast, cationic substitution of copper by cobalt increases the magnetic anisotropy due to a strong contribution from the latter ion.

中文翻译：

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具有强粒子间相互作用的混合硫尖晶石 CuCr 2 S x Se 4-x (x = 0; 2) 和 Co x Cu 1-x Cr 2 S 4 (x = 0.1; 0.2) 纳米晶体的磁共振研究

摘要 研究了混合硫尖晶石纳米晶体 CuCr2SxSe4−x (x = 0 和 2) 和 CoxCu1−xCr2S4 (x = 0.1 和 0.2) 的磁共振特性。基于 TEM、SEM 和共振数据已经确定，所有样品都包含尺寸为 1 至 50 m 的压实纳米尺寸微晶的块和尺寸为 10 至 30 nm 的单个纳米颗粒。这些研究提供了所有样品中强烈的颗粒间相互作用导致高封闭温度值的证据。磁偶极场出现在低于阻塞温度的相互作用的相邻纳米晶体的边界区域。这导致磁共振谱的不均匀展宽以及附加吸收线的出现。随着低温下磁各向异性的增加，由于纳米粒子中的矩冻结，无论是在单个还是压实的纳米粒子中，都观察到共振场随着线加宽的变化。在冷冻温度 Tfr 以下建立共振谱的有隙特性，其能隙由平均磁各向异性定义。硒对硫的阴离子取代导致磁各向异性降低。相比之下，钴对铜的阳离子取代会增加磁各向异性，因为后者离子的贡献很大。在冷冻温度 Tfr 以下建立共振谱的有隙特性，其能隙由平均磁各向异性定义。硒对硫的阴离子取代导致磁各向异性降低。相比之下，钴对铜的阳离子取代会增加磁各向异性，因为后者离子的贡献很大。在冷冻温度 Tfr 以下建立共振谱的有隙特性，其能隙由平均磁各向异性定义。硒对硫的阴离子取代导致磁各向异性降低。相比之下，钴对铜的阳离子取代会增加磁各向异性，因为后者离子的贡献很大。