A mixture of soft–hard (S–H) ferrites with the general chemical formula (1‐x) Ni0.5Cu0.25Zn0.25Fe2O4 (NCZFO) + (x) SrFe11Y1O19 (SFYO) is developed via sol‐gel auto‐combustion and their physical mixing. X‐ray diffraction (XRD), Fourier transform infrared spectroscopy, field emission scanning electron microscopy (SEM) coupled with energy dispersive X‐ray spectroscopy, high‐resolution transmission electron microscopy (HRTEM), vibrating sample magnetometry (VSM) and two‐probe technique are used to examine the resultant materials. Rietveld refinement of XRD data confirms the co‐existence of both soft and hard phases in the composites. The HRTEM and FESEM results confirm the nanocrystalline nature of the synthesized particles. Williamson‐Hall method is employed to reveal the strain nature in soft and hard phases. VSM analysis shows considerable changes in the magnetic characteristics for the different composition of NCZFO and SFYO. The exchange‐spring mechanism is discussed in the manuscript.

中文翻译：

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(1-x) Ni0.5Cu0.25Zn0.25Fe2O4 + (x) SrFe11Y1O19 软硬铁氧体复合纳米粒子的应变和交换弹簧机制

软硬 (S–H) 铁氧体的混合物，其化学通式为 (1‐X） 你0.5铜0.25锌0.25铁2氧4(NCZFO) + (X) 锶铁矿11是1氧19（SFYO）是通过溶胶凝胶自动燃烧及其物理混合开发的。X 射线衍射 (XRD)、傅里叶变换红外光谱、场发射扫描电子显微镜 (SEM) 与能量色散 X 射线光谱、高分辨率透射电子显微镜 (HRTEM)、振动样品磁强计 (VSM) 和双探针技术用于检查所得材料。Rietveld 对 XRD 数据的精修证实了复合材料中软相和硬相的共存。HRTEM 和 FESEM 结果证实了合成颗粒的纳米晶性质。Williamson-Hall 方法用于揭示软相和硬相的应变性质。VSM 分析显示，不同成分的 NCZFO 和 SFYO 的磁特性发生了相当大的变化。手稿中讨论了交换弹簧机制。