Magneten

Magneten are objects that produce a magnetic field and attract ferromagnetic materials such as iron. They can be permanent, maintaining a magnetic field without external power, or electromagnets, which generate a field only when an electric current passes through a coil surrounding a magnetic core.

Permanent magnets are made from materials with high magnetic anisotropy and coercivity. Common modern types include ferrite (ceramic) magnets, alnico, and rare-earth magnets such as neodymium-iron-boron (NdFeB) and samarium-cobalt (SmCo). Electromagnets consist of a coil of wire around a magnetic core, typically iron; their field strength can be adjusted by changing the current.

Magnetic properties are described by terms such as magnetization, remanence, and coercivity. The magnetic field strength is measured in teslas (T) or gauss (1 T = 10,000 gauss). The basic mechanism involves magnetic domains aligning in response to external fields; in permanent magnets the domains remain aligned after magnetization.

Magneten have wide applications in industry and daily life: electric motors, generators, transformers, loudspeakers, data storage devices, magnetic resonance imaging (MRI), and many sensors. They also occur naturally in lodestone, a mineral form of magnetite, which was the first known magnet.

Safety and handling considerations include the strong attraction of magnets to metal objects and to each other, which can cause injury or damage to devices if misused, especially with large neodymium magnets.