In this letter, the influence of spin-transfer torque (STT) on magnetic read sensor noise in the test band of 1–200 MHz has been investigated experimentally using the macrospin model with STT term. The results reveal a dependence of the integrated noise power on the direction of bias current when an external field is applied. In a positive field direction, positive bias current produces stronger noise than negative current. In the presence of negative field direction, the relationship is reversed. The hypothesis of asymmetric oscillation noise modification by STT is confirmed by corresponding changes of a correlation between the signal in the test band, and amplitude fluctuations of thermally driven ferromagnetic resonance in the sensor free layer, both derived from high-bandwidth waveforms. The effect is a consequence of the spin torque impact on the effective damping constant, which adjusts the shape of the asymmetric oscillation spectrum in a test band.

中文翻译：

---

非对称振荡引起的磁性低频噪声中的自旋扭矩效应

在这封信中，使用带有 STT 项的宏自旋模型，通过实验研究了自旋转移矩 (STT) 对 1-200 MHz 测试频带内磁读取传感器噪声的影响。结果表明，当施加外场时，集成噪声功率依赖于偏置电流的方向。在正磁场方向上，正偏置电流比负电流产生更强的噪声。在存在负场方向的情况下，这种关系是相反的。通过测试带中信号与传感器自由层中热驱动铁磁共振的振幅波动之间的相关性的相应变化证实了 STT 不对称振荡噪声修正的假设，两者均源自高带宽波形。