antimagnetic

Antimagnetic describes objects or materials that are designed to resist the influence of external magnetic fields, reducing or preventing unwanted magnetization or interference. The term is commonly used in horology to describe watches that remain accurate when exposed to magnetic fields.

In scientific terms, magnetism arises from electron spins and orbital motions. Materials can be diamagnetic, paramagnetic, or ferromagnetic, with varying responses to external fields. Antimagnetic is not a precise scientific classification; it is a practical designation for strategies that minimize magnetic effects. These strategies include using non-magnetic alloys for components, employing magnetic shielding, and avoiding ferromagnetic materials in critical parts of a device. Soft magnetic shielding or enclosing sensitive mechanisms in a high-permeability case are common approaches to divert or attenuate magnetic fields.

Applications and use cases vary. In watches, antimagnetic movements aim to reduce timing errors caused by nearby magnets. This is often achieved through a combination of non-magnetic materials for gears and springs, as well as shielding such as a soft iron inner cage that surrounds the movement. In other devices, antimagnetic design helps ensure reliable operation in environments with strong magnetic fields, such as medical equipment, industrial instruments, and certain outdoor or aerospace applications. It is important to note that marketing claims of “antimagnetic” performance can vary, and independent testing or standards may be used to verify magnetic resistance.

Related concepts include diamagnetism, magnetic shielding, and magnetic susceptibility. Antimagnetic should not be confused with antiferromagnetism, which describes a microscopic arrangement of magnetic moments that cancels magnetization.