$L{\text{V}}_4{\text{O}}_8\left(L=\text{Yb},\text{Y},\text{Lu}\right)$ compounds are reported to crystallize in a structure similar to that of the orthorhombic ${\text{CaFe}}_2{\text{O}}_4$ structure type and contain four inequivalent V sites arranged in zigzag chains. We confirm the structure and report the magnetic, thermal, and transport properties of polycrystalline ${\text{YV}}_4{\text{O}}_8$ and ${\text{LuV}}_4{\text{O}}_8$. A first-order-like phase transition is observed at 50 K in both ${\text{YV}}_4{\text{O}}_8$ and ${\text{LuV}}_4{\text{O}}_8$. The symmetry remains the same with the lattice parameters changing discontinuously. The structural transition in ${\text{YV}}_4{\text{O}}_8$ leads to partial dimerization of the V atoms resulting in a sudden sharp drop in the magnetic susceptibility. The V spins that do not form dimers order in a canted antiferromagnetic state. The magnetic susceptibility of ${\text{LuV}}_4{\text{O}}_8$ shows a sharp peak at $\sim 50\text{K}$. The magnetic entropies calculated from heat capacity versus temperature measurements indicate bulk magnetic transitions below 90 K for both ${\text{YV}}_4{\text{O}}_8$ and ${\text{LuV}}_4{\text{O}}_8$.

• Received 24 September 2009

DOI:https://doi.org/10.1103/PhysRevB.81.104432