Magnetism in the perovskite KAgF3

Silver II fluorides (containing the spin-1/2 Ag2+ ion) bear many similarities to the high-Tc cuprates (containing the spin-1/2 Cu2+ ion). However, these exotic fluorides are difficult to prepare and few groups have the expertise to pursue the necessary fluorine chemistry. Recently, high-quality samples of KAgF3 have been prepared, a compound which has a distorted perovskite structure and exhibits a plethora of interesting magnetic transitions whose origin remains to be clarified. We propose to study KAgF3 using zero-field muSR through all the putative transitions because the technique is ideal for distinguishing between bulk transitions and impurity effects. The key aim of the experiment though is to discover how the extremely large intrachain superexchange interactions are manifested in the actual magnetic ground state in this fascinating compound.