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.

The Bohr van Leeuwen theorem states that any plasma with a kinetic equilibrium will reach a state where this phenomenon is zero. Free electron gases display the Landau type of this property, and materials exhibiting it have negative susceptibility. Superconductors display the "perfect" variety of this property in the Meissner Effect. This property is often described as Lenz's Law applied on a microscopic scale, and it was originally though to violate Earnshaw's Theorem. This property is exhibited by pyloric graphite and bismuth, and materials displaying it can be levitated for a few seconds. For 10 points, name this form of magnetism that expels applied magnetic fields.
Science