We investigated the appropriateness of a tunneling magnetoresistance (TMR)-based magnetometer for detecting geomagnetic fields with long-period oscillations through observation of the geomagnetic pulsation (Pi). Pi was not sufficiently observed in the raw outputs due to thermal noise; a bandwidth-limitation treatment helped extract Pi without data stacking. The detectable intensity was reduced to 1 nT with a period of 30s, but detection was impossible for 100s. The frequency characteristics revealed that reducing the cutoff frequency of a TMR magnetometer is a promising approach for detecting field oscillations occurring over long periods, such as 100s.

我们通过观察地磁脉动 (Pi) 研究了基于隧道磁阻 (TMR) 的磁力计用于检测具有长周期振荡的地磁场的适用性。由于热噪声，未在原始输出中充分观察到 Pi；带宽限制处理有助于在没有数据堆叠的情况下提取 Pi。可检测强度在 30 秒内降至 1 nT，但在 100 秒内无法检测。频率特性表明，降低 TMR 磁力计的截止频率是检测长时间（例如 100 秒）发生的场振荡的有前途的方法。