Exploring Magnetic Interactions of an Mo$_3$O$_{13}$ Trimer Containing Compound: La$_5$Mo$_6$O$_{21}$

When searching for exotic magnetic ground states, it is often useful to seek out materials with certain geometric networks such as: triangular, kagome, and even square lattices with uniform magnetic exchange. Recently, the formation of a condensed valence bond state was proposed to explain the physical properties of LiZn$_2$Mo$_3$O$_8$. This low-temperature ground state emanates from the interactions of one unpaired electron residing on the Mo$_3$O$_{13}$ magnetic subunits. Thus, compounds containing related Mo$_3$O$_{13}$ subunits may prove to be a fertile playground for the study of magnetic interactions between these molecule-like clusters. Earlier structural reports of La$_5$Mo$_6$O$_{21}$ showed that this compound was built from these subunits, as well as, 1-D ``double lambda'' perovskite-like MoO$_6$ octahedra. The Mo atoms residing on the Mo$_3$O$_{13}$ trimers and the double lambda units have oxidation states of 4+ and 5+, respectively. Consequently, the magnetic response and entropy loss ca. 10 K are likely due to the magnetic interactions between the double lambda units and not the Mo$_3$O$_{13}$ trimers. In this presentation, the analysis of the total neutron scattering of La$_5$Mo$_6$O$_{21}$ will be used to draw correlations between the structure and the properties.