Crystal Growth of a frustrated J ₁– J ₂ chain magnet NaCuMoO₄(OH)

In a frustrated J ₁– J ₂ chain magnet with ferromagnetic nearest neighbor interactions J ₁ and antiferromagnetic next-nearest neighbor interactions J ₂, novel quantum states such as a spin nematic state are theoretically expected to be present. To detect the novel states experimentally, it is required to find a suitable model compound and to obtain its sizeable and high-quality single crystals. Here we report synthesis of a single-crystalline NaCuMoO₄(OH), a model compound of frustrated J ₁– J ₂ chain magnet, by a hydrothermal method and discuss its magnetic properties. The temperature dependencies of magnetization are almost consistent with those of powder samples at high temperatures, while the peak in heat capacity divided by temperature associated with a magnetic transition becomes sharper and larger in the single crystal. This indicates the improved quality of the single-crystalline sample compared with the powder sample. Single-crystalline NaCuMoO₄(OH) should give a new experimental approach to the novel spin-nematic states expected near 26 T. (paper)