Koersivitet

Koersivitet is a term used in magnetism to describe the resistance of a ferromagnetic material to demagnetization. It is a measure of how strongly a magnetic field must be applied in the reverse direction to reduce the magnetization of a material to zero after it has been saturated. Materials with high koersivitet are difficult to demagnetize and are known as "hard" magnetic materials. Conversely, materials with low koersivitet are easily demagnetized and are called "soft" magnetic materials.

The koersivitet of a material is an important property that determines its suitability for various applications. For permanent magnets, which are designed to retain their magnetization over long periods, high koersivitet is essential. Examples of materials with high koersivitet include neodymium magnets and samarium-cobalt magnets, which are used in electric motors, loudspeakers, and data storage devices.

Soft magnetic materials, on the other hand, are used in applications where the magnetic field needs to be easily switched on and off, such as in transformers, inductors, and magnetic shielding. These materials typically have low koersivitet and include soft iron and silicon steel. The koersivitet is typically measured in amperes per meter (A/m) or oersteds (Oe). It is an intrinsic property of the material and is influenced by factors such as crystal structure, grain size, and the presence of impurities. Understanding koersivitet is crucial for selecting the appropriate magnetic materials for specific technological needs.