Heat-assisted magnetic recording is a future hard disk drive (HDD) technology for extremely increasing areal density. The tunneling magnetoresistive (TMR) device structure, located inside the magnetic read–write head of a hard drive, is the most complex and sensitive component, which contains sensitive components, such as a touchdown sensor and a near-field transducer. The laser used in the writing process might cause degradation of magnetic head components. The effects of laser irradiation on the TMR device have been investigated using a quasi-static test measurement to observe the characteristic changes of the magnetic response sensitivity function. The results showed only the amplitude degradation, as the resistance and asymmetry parameters were unchanged. The nanostructure of the degradation TMR devices was investigated by using scanning transmission electron microscopy and X-ray energy-dispersive spectrometry. It was found that the manganese depletion in the antiferromagnetic layer causes a nonactive zone due to the poor magnetic coupling pinning function and reduces the functioning of the HDD. The ratio of active and nonactive zone elements has a strong correlation to the amplitude degradation of individual TMR devices. The TMR structure with shorter strip height can have a higher risk of device degradation.

中文翻译：

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激光辐照磁数据记录头的显微结构和隧道磁阻特性

热辅助磁记录是一种未来的硬盘驱动器 (HDD) 技术，可极大地提高面密度。隧道磁阻 (TMR) 器件结构位于硬盘驱动器的磁读写头内部，是最复杂和最敏感的组件，其中包含敏感组件，例如触地传感器和近场传感器。写入过程中使用的激光可能会导致磁头组件退化。已经使用准静态测试测量研究了激光照射对 TMR 器件的影响，以观察磁响应灵敏度函数的特征变化。结果仅显示幅度退化，因为电阻和不对称参数没有变化。通过使用扫描透射电子显微镜和 X 射线能量色散光谱法研究了降解 TMR 器件的纳米结构。发现反铁磁层中的锰耗尽会由于磁耦合钉扎功能差而导致非活性区，并降低了 HDD 的功能。有源和无源区元素的比率与单个 TMR 设备的幅度退化有很强的相关性。具有较短条带高度的 TMR 结构可能具有较高的器件退化风险。有源和无源区元素的比率与单个 TMR 设备的幅度退化有很强的相关性。具有较短条带高度的 TMR 结构可能具有较高的器件退化风险。有源和无源区元素的比率与单个 TMR 设备的幅度退化有很强的相关性。具有较短条带高度的 TMR 结构可能具有较高的器件退化风险。