Magnetic field influence on the Néel, dimer, and spin-liquid states of the low-dimensional antiferromagnetsNiTa2O6andCoSb2O6

Magnetic susceptibility and heat capacity measurements are used to infer information about the short-range magnetic order above the N\'eel temperature ${T}_{N}$ and the antiferromagnetically ordered states below ${T}_{N}$ of quasi-one-dimensional (quasi-1D) ${\mathrm{CuSb}}_{2}{\mathrm{O}}_{6},\phantom{\rule{0.16em}{0ex}}{\mathrm{NiTa}}_{2}{\mathrm{O}}_{6}$, and ${\mathrm{CoSb}}_{2}{\mathrm{O}}_{6}$. It is shown that two antiferromagnetic sublattices, oriented at $90{}^{\ensuremath{\circ}}$ to one another, are likely present in ${\mathrm{NiTa}}_{2}{\mathrm{O}}_{6}$ and ${\mathrm{CoSb}}_{2}{\mathrm{O}}_{6}$. Application of magnet field parallel to the quasi-1D chains of one sublattice is perpendicular to the chains of the other sublattice. This results in two antiferromagnetic transitions when the magnetic field $H\ensuremath{\ge}2$ T ($\ensuremath{\sim}0.2$ meV). The anisotropic influence of magnetic field on the antiferromagnetic state leads to a magnetocaloric effect that is fully investigated in this work. The effect is associated with competition among N\'eel, dimer, and spin-liquid states that are all present at ${T}_{N}$.