1∕3magnetization plateau observed in the spin-1∕2trimer chain compoundCu3(P2O6OH)2

Abstract

We report magnetic properties of ${\mathrm{Cu}}_{3}{({\mathrm{P}}_{2}{\mathrm{O}}_{6}\mathrm{O}\mathrm{H})}_{2}$. A spin-$1∕2$ trimer chain with ${J}_{1}\ensuremath{-}{J}_{2}\ensuremath{-}{J}_{2}$ interactions exists, where ${J}_{1}$ and ${J}_{2}$ denote two antiferromagnetic (AF) exchange interactions. A $1∕3$ magnetization plateau was observed above $12\phantom{\rule{0.3em}{0ex}}\mathrm{T}$ in a magnetization curve at $1.6\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. The appearance of the plateau is consistent with the theorem of Oshikawa, Yamanaka, and Affleck [Phys. Rev. Lett. 78, 1984 (1997)]. Experimental results of magnetic susceptibility and magnetization agree well with quantum Monte Carlo results for the trimer chain with ${J}_{1}=95$ and ${J}_{2}=28\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. To our knowledge, ${\mathrm{Cu}}_{3}{({\mathrm{P}}_{2}{\mathrm{O}}_{6}\mathrm{O}\mathrm{H})}_{2}$ is the first model compound of trimer chains with only AF interactions showing a magnetization plateau.