Instructions: 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.
Input: This property is displayed by ProHance, Optimark, and other Gadolinium-containing MRI contrast agents. HAMR drives curcumvent the size limits for one form of this phenomenon, and that form has a relaxation time proportional to the exponential of the nanoscale anisotropy times the volume, according to the Arrhenius-Neel law. On a bulk scale, ferrofluids display the super- version of this phenomenon. This phenomenon is proportional to the hyperbolic tangent of mu B over k T according to the Langevin law, which in one regime reduces to M equals C times B divided by T, a law named for Curie. This phenomenon occurs above the Curie point in some materials, and materials that exhibit it have positive magnetic susceptibility. For 10 points, name this type of magnetism in which domains will weaky align with an applied field.
Output:
Science