Long-term outdoor observation of geomagnetic fields using tunneling magnetoresistance-based magnetometer and detection of long-period oscillations of geomagnetic pulsations: prospects for earthquake disaster prevention
- Resource Type
- Authors
- Kan Okubo; Yuto Oishi; Chikara Furukawa; Nobuhito Ohnishi; Shinji Isogami
- Source
- Applied Physics Express. 14:056502
- Subject
- Earth's magnetic field
Materials science
Magnetoresistance
Magnetometer
law
Long period
General Engineering
General Physics and Astronomy
Earthquake disaster
Geophysics
Quantum tunnelling
Term (time)
law.invention
- Language
- ISSN
- 1882-0786
1882-0778
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 30 s, but detection was impossible for 100 s. 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 100 s.