Earlier, we reported exchange coupling between bilayers of CoFe₂O₄/CoFe₂, where CoFe₂O₄ and CoFe₂ are the hard and soft magnetic layers, respectively. These results suggested trilayers structures of CoFe₂O₄/CoFe₂/CoFe₂O₄ are strong candidates for low hysteresis loss “exchange spring materials.” To study this possibility, we extended our investigation to the synthesis of CoFe₂O₄/CoFe₂/CoFe₂O₄ trilayers under different sputtering deposition conditions, which included oxygen pressure in the case of the CoFe₂O₄ component and the application of a magnetic field during the deposition of the soft CoFe₂. The most significant finding was an increase in the exchange spring figure of merit (FoM) of 36% in-plane and 60% out-of-plane by the application of an applied field during the deposition of the soft CoFe₂, resulting in a decrease in hysteretic losses by a similar percentage. We will discuss these spin spring results in terms of an increase in uniaxial anisotropy energy in the CoFe₂ layers due to short-range ordering of Fe–Fe and Co–Co pairs during deposition and an enhancement in the coercivity and remnant magnetization of CoFe₂O₄. We also discuss a metric (FoM) for describing enhancements due to multiple optimized deposition conditions.

中文翻译：

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CoFe2O4/CoFe2/CoFe2O4 薄膜中的磁感应增强交换弹簧效应

早些时候，我们报道了 CoFe ₂ O ₄ /CoFe ₂双层之间的交换耦合，其中 CoFe ₂ O ₄和 CoFe ₂分别是硬磁层和软磁层。这些结果表明 CoFe ₂ O ₄ /CoFe ₂ /CoFe ₂ O _{4 的}三层结构是低磁滞损耗“交换弹簧材料”的有力候选者。为了研究这种可能性，我们将研究扩展到 CoFe ₂ O ₄ /CoFe ₂ /CoFe ₂ O ₄的合成在不同溅射沉积条件下的三层，包括在 CoFe ₂ O ₄组分的情况下的氧压力和在软 CoFe ₂沉积期间施加磁场。最重要的发现是通过在软 CoFe ₂沉积期间施加外加场，交换弹簧品质因数 (FoM) 增加了 36% 平面内和 60% 平面外，导致滞后损失减少了类似的百分比。我们将根据 CoFe ₂中单轴各向异性能量的增加来讨论这些自旋弹簧结果由于在沉积过程中 Fe-Fe 和 Co-Co 对的短程有序以及 CoFe ₂ O ₄的矫顽力和剩余磁化强度的增强，层。我们还讨论了一个指标 (FoM)，用于描述由于多种优化沉积条件而产生的增强。