Open AccessLong-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
Author(s) -
Shinji Isogami,
Yuto Oishi,
Chikara Furukawa,
Nobuhito Ohnishi,
Kan Okubo
Publication year - 2021
Publication title -
applied physics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.911
H-Index - 94
eISSN - 1882-0786
pISSN - 1882-0778
DOI - 10.35848/1882-0786/abf66a
Subject(s) - magnetometer , earth's magnetic field , ultra low frequency , physics , geophysics , magnetoresistance , magnetic field , stacking , term (time) , geodesy , nuclear magnetic resonance , geology , acoustics , astronomy , quantum mechanics
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.