What is magnetic coercivity;give examples of it in at least 1 one experiment?
In materials science, the coercivity, also called the coercive field, of a ferromagnetic material is the intensity of the applied magnetic field required to reduce the magnetization of that material to zero after the magnetization of the sample has been driven to saturation. Coercivity is usually measured in oersted or ampere/meter units and is denoted HC. Coercivity measures the resistance of a ferromagnetic material to becoming demagnetized. Coercivity can be measured using a B-H Analyzer. Materials with high coercivity are called hard ferromagnetic materials, and are used to make permanent magnets. Permanent magnets find application in electric motors, magnetic recording media (e.g. hard drives, floppy disks, or magnetic tape) and magnetic separation. A material with a low coercivity is said to be soft and may be used in microwave devices, magnetic shielding, transformers, or recording heads. As for an experiment, it is used in magnetic information storage. The main challenge in designing magnetic information storage media is to retain the magnetization of the medium despite thermal fluctuations caused by the superparamagnetic limit. If the thermal energy is too high, there may be enough energy to reverse the magnetization in a region of the medium, destroying the data stored there. The energy required to reverse the magnetization of a magnetic region is proportional to the size of the magnetic region and the magnetic coercivity of the material. The larger the magnetic region is and the higher the magnetic coercivity of the material, the more stable the medium is. There is a minimum size for a magnetic region at a given temperature and coercivity. If it is any smaller it is likely to be spontaneously de-magnetized by local thermal fluctuations. Perpendicular recording uses higher coercivity material because the head's write field penetrates the medium more efficiently in the perpendicular geometry. Hope this helps!
