Given the task definition and input, reply with output. In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.

This property is present in elements above the horizontal axis in the Bethe-Slater curve, and it only occurs in materials with one or more easy axes. Coercivity and remanence are characteristic properties of materials with this property that increases in discrete steps as shown by the Barkhausen effect. Owing to a (*) hysteresis loop, this property remains in a material even after an applied field is removed, though it disappears when a material is raised above the Curie temperature. Bulk materials with this property consist of domains of aligned spins. Cobalt, but not copper, possesses, for 10 points, what form of permanent magnetism named after iron
Science