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Chemical doping is a powerful method of controlling the physical properties of magnetic materials. Unlike the uniform changes brought about by pressure-induced parameter tuning, chemical doping introduces randomness into the system. This randomness can sometimes lead to unintended consequences, but it can also reveal unexpected, unique physics. The first part of the talk will detail how the dilution of magnetic ions can suppress the effective magnetic interactions, leading to a quantum disordered phase that differs from the traditional percolation disorder. The second part of the talk will focus on a field-induced phase transition that arises from the asymmetry of single-ion anisotropy between different ions, and therefore does not occur when the system consists of a single type of magnetic moment. Both cases demonstrate the extent to which we can tune the physical property by substituting magnetic ions, and the emergence of new physical phenomena rooted in the effects of randomness.

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Yoshito Watanabe
Seminar Room of the Institute of Physics II
Contact: Simon Trebst