Low Temperature 1D-Ising-like Behaviour of Cobalt Niobate

Cobalt niobate, CoNb$_{2}$O$_{6}$, is a material that exhibits 1D-Ising-like behaviour at low temperatures, based primarily on chains of spins of the Co$^{2+}$ atoms. Specific heat and magnetic susceptibility measurements on cobalt niobate have found magnetic transitions at 1.9 K and 2.9 K, in agreement with previous work. Specifically, we have performed specific heat measurements in zero field down to 330 mK and have mapped some of the field dependence of the specific heat above 2 K. The low temperature specific heat measurements show an increasingly long relaxation time, implying that the spins become increasingly decoupled from the lattice with decreasing temperature. We have also been the first group to examine the magnetic properties of this material with muon spin rotation ($\mu$SR). This work found that the cobalt moments remain largely dynamic on the microsecond timescale for temperatures well below 1.9 K, indicating that the ground state of CoNb$_{2}$O$_{6}$ is more complex than previously thought.