Abstract
We report a structural-magnetic investigation by x-ray absorption spectroscopy (XAS), neutron diffraction, dc susceptibility , and electron spin resonance (ESR) of the 12R-type perovskite . Our structural analysis by neutron diffraction supports the existence of structural trimers with chemically disordered occupancy of and ions, with the valence of the Mn ions confirmed by the XAS measurements. The magnetic properties are explored by combining dc-susceptibility and -band (9.4 GHz) electron spin resonance, both in the temperature interval of K. A scenario is presented under which the magnetism is explained by considering magnetic dimers and trimers, with exchange constants K and K, and orphan spins. Thus, is proposed as a rare case of an intrinsically disordered spin gap system with a frustrated ground state.
- Received 27 May 2014
- Revised 7 May 2015
DOI:https://doi.org/10.1103/PhysRevB.91.224416
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