The alteration of the microstructure and magnetic performance of an exchange bias system, induced by ion irradiation, adversely affects the practical application of spintronic/storage devices in extreme environments. Here, we report systematically the correlation between static and dynamic magnetism and microstructure changes in NiFe/NiO exchange-biased bilayers after high-energy Xe+ ion irradiation. The effect of cascade collision induced by irradiation on exchange bias is studied through Monte Carlo simulations. It is distinguished from the traditional modification caused by keV-level ion irradiation. At low doses, the transition from amorphous to recrystallization occurs in the NiFe layer and the anomalous exchange bias behavior is induced. A step-like structure appears in the magnetic hysteresis loop and the step gradually shifts downward as the dose increases. At high doses, the exchange bias effect is suppressed due to the disordered antiferromagnetic moment caused by heat accumulation during cascade collision, which significantly decreases the thermal stability of the sample by 5–6 times. In addition, the non-monotonic evolution of high-frequency magnetic properties is observed with increasing irradiation doses. This work provides important foundational data for designing future spintronic/memory devices to enhance radiation tolerance and stability.

中文翻译：

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高能 Xe+ 离子辐照引起的 NiFe/NiO 双层的异常交换偏压行为

离子辐照引起的交换偏置系统的微观结构和磁性能的改变会对自旋电子/存储器件在极端环境中的实际应用产生不利影响。在这里，我们系统地报告了高能 Xe+ 离子辐照后 NiFe/NiO 交换偏置双层的静态和动态磁性与微观结构变化之间的相关性。通过蒙特卡罗模拟研究了辐照引起的级联碰撞对交换偏压的影响。它与keV级离子辐照引起的传统改性不同。在低剂量下，NiFe 层发生从非晶态到再结晶的转变，并引发异常交换偏置行为。磁滞回线中出现阶梯状结构，并且随着剂量的增加，阶梯逐渐向下移动。在高剂量下，由于级联碰撞过程中热量积累引起的无序反铁磁矩，交换偏置效应被抑制，这使样品的热稳定性显着降低了5-6倍。此外，随着辐照剂量的增加，观察到高频磁特性的非单调演化。这项工作为设计未来的自旋电子/存储器件以增强辐射耐受性和稳定性提供了重要的基础数据。