Interacting nanoscale magnetic superatom cluster arrays in molybdenum oxide bronzes

Abstract

In this study, we examine several reduced ternary molybdates in the family of yellow rare earth molybdenum bronzes produced by electrochemical synthesis with composition LnMo₁₆O₄₄. These compounds contain an array of electrically isolated but magnetically interacting multi-atom clusters with composition Mo₈O₃₆. These arrayed superatom clusters support a single hole shared among the eight molybdenum atoms in the unit, corresponding to a net spin moment of 1μ_B, and exhibit magnetic exchange between the units via the MoO₄ tetrahedra (containing Mo⁶⁺ ions) and the LnO₈ cubes (containing Ln³⁺ ions). The findings presented here expand on the physics of the unusual collective properties of multi-atom clusters and extend the discussion of such assemblages to the rich structural chemistry of molybdenum bronzes.