koerzitivität

Koerzitivität, often referred to as coercivity, is a fundamental property of ferromagnetic materials that quantifies their resistance to demagnetization. It represents the magnetic field strength required to reduce the magnetization of a material to zero after it has been magnetized to saturation. In essence, it's a measure of how "hard" it is to reverse the magnetic orientation within a material.

Materials with high koerzitivität are known as hard magnetic materials. They are capable of retaining their magnetization even in the presence of strong external magnetic fields, making them suitable for permanent magnets. Examples include alloys of iron, nickel, and cobalt, as well as rare-earth magnets like neodymium-iron-boron. These materials are crucial for applications where a stable magnetic field is needed, such as in electric motors, loudspeakers, and magnetic storage devices.

Conversely, materials with low koerzitivität are called soft magnetic materials. They are easily magnetized and demagnetized, which makes them ideal for applications where the magnetic field needs to change rapidly or be switched on and off. Examples include pure iron and silicon steel. Soft magnetic materials are commonly used in transformers, inductors, and magnetic shielding. The koerzitivität of a material is an important parameter for engineers designing magnetic devices, as it directly influences the performance and efficiency of the system. It is typically measured in units of amperes per meter (A/m) or oersteds (Oe).