Earth's field magnetometry

Abstract

Rep. Prog. Phys.!1972[35 803-881 limitations. Details of electronic detection systems are not described except where appropriate reference cannot be included.The instruments described are in the following main classifications : magnetometers using nuclear and atomic resonance, saturable cores, suspended magnets, induction coils and superconducting devices.In addition, the magnetometer systems which use artificially created fields to allow vector measurements to be made by total field sensors are described. Their operation performance is assessed and the use of bias and backing-off fields are discussed.The use of the proton gyromagnetic ratio as the absolute standard of geomagnetic field measurement is summarized. There follow-s a discussion of the requirement for routine ground-based geomagnetic data to be supplied to the scientific community in digital form for direct machine read-in, and some speculation about practicable automatically recording observatory systems.

Magnetic field imaging with microfabricated optically-pumped magnetometers

“…On a very small scale, nitrogen vacancy color centers in diamond have been used to create magnetic images of living magnetotactic bacteria with sub-micrometer spatial resolution [1]. On a larger scale, magnetometers are routinely used to map areas of many square kilometers for prospecting, archeology, and magnetic anomaly detection [2]. On a very large scale, space-based magnetometers are used to map the magnetic field of the Earth [3] and other planets and their moons from satellites and spacecraft [4].…”

Induction in the Earth's crust: Observational methods on land and sea

“…Stuart (1972) and Serson (1973)have presented reviews of the devices used. They can be classified in five groups: Nuclear magnetic resonance or optical pumping devices measure the modulus of the total field independently of its direction.…”

Development of a polymeric magnetostrictive fiber-optic sensor system

“…Among the non-optical sensors, there are several currently available in the market. They varies from simple device such as search coil magnetometer commonly used in treasure hunt using Faraday's law of induction [1], fluxgate sensor measure magnetic field by comparing the drive-coil current needed to saturate the core in one direction as oppose to the opposite direction [2], Hall-effect sensor which based on voltage induction by moving charges in the sensor experiencing Lorentz force [3], stress-induced magnetoelastic devices such as magnetostrictive amorphous metal ribbon [4], or currently most sensitive superconducting quantum interference device (SQUIDS) which commonly employed to measure remnant magnetization and susceptibility of geophysical or biomagnetic samples [5]. These sensors are relatively simple in design and also offer very good sensitivity (<10 -5 gauss).…”