Task: Text Categorization
Input (English): One of Nesper's criteria states that if a Zintl phase has this property, then that property must be temperature-dependent. Gorter developed an empirical equation describing absorption due to this property, and Al'tshuler developed a theory of (*) relaxation in lanthanides due to this property. Two theories of this property are named after Brilouin and Langevin. The van Vleck form of this property is temperature-independent, and its weakest form was explained in terms of Fermi-Dirac statistics by Pauli. Certain types of oximetry take advantage of the fact that oxygen has this property, which occurs above the Curie temperature. For 10 points, name this type of magnetism found in substances with unpaired electrons.
Output (English): Science