magnétomètres

A magnetometer is an instrument used to measure magnetic fields. These fields can be generated by permanent magnets, electric currents, or by magnetic minerals in the Earth. Magnetometers are used in a wide variety of applications, including geology, geophysics, archaeology, and navigation.

There are several types of magnetometers, each with different operating principles and sensitivities. Fluxgate magnetometers are common and work by measuring the change in magnetic flux through a ferromagnetic core. They are relatively inexpensive and robust. Proton precession magnetometers measure the magnetic field by detecting the precession frequency of protons in a fluid. They are known for their accuracy and ability to measure the total magnetic field strength. Overhauser magnetometers are a type of proton magnetometer that offers higher sensitivity and faster readings by using a polarizing agent. SQUID (Superconducting Quantum Interference Device) magnetometers are extremely sensitive and are used in research applications such as magnetoencephalography (MEG) to map brain activity. Other types include Hall effect sensors and anisotropic magnetoresistance (AMR) sensors, which are often used in smaller electronic devices.

Applications for magnetometers are diverse. In geophysics, they are used to map variations in the Earth's magnetic field, which can indicate the presence of mineral deposits or geological structures. Archaeologists use magnetometers to detect buried artifacts or features that have altered the local magnetic field. In navigation, magnetometers help determine orientation by sensing the Earth's magnetic poles. They are also integrated into smartphones and other devices for compass functionalities. Scientific research utilizes magnetometers to study magnetic materials, cosmic magnetic fields, and even the magnetic properties of biological organisms.