| We discuss the physics of dilute magnetic impurities and vacancies in frustrated magnets with non-collinear order in the ground state. Taking the triangular-lattice Heisenberg model as an example, we use quasiclassical methods to determine the impurity contributions to the magnetization and susceptibility. Interestingly, each impurity moment is not quantized, but receives non-universal screening corrections because frustration is relieved locally. At finite temperatures in two dimensions, where bulk long-range order is absent, this implies an impurity-induced magnetic response of Curie form, with a prefactor corresponding to a fractional moment per impurity. |
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