highcoercivity
High coercivity refers to magnetic materials that resist demagnetization by external magnetic fields. Coercivity, Hc, is the reverse field required to reduce the material’s magnetization to zero after it has been saturated. Materials with high Hc are called hard magnets or permanent magnets, as opposed to soft magnets that exhibit low coercivity and fast magnetization changes.
High coercivity arises from a combination of intrinsic and extrinsic factors. Intrinsic factors include large magnetocrystalline
Common high-coercivity materials include NdFeB magnets, SmCo magnets, and, historically, Alnico and ferrites in certain grades.
Applications rely on high Hc to maintain magnetization in strong opposing fields and temperatures, including electric