Low-temperature metastable states in a stacked triangular Ising antiferromagnet

We study low-temperature magnetization processes in a stacked triangular Ising antiferromagnet by Monte Carlo simulations. In increasing and decreasing magnetic fields we observe multiple steps and hysteresis corresponding to formation of different metastable states. Besides the equidistant threefold splitting of the 1/3 ferrimagnetic plateau, we additionally confirm a fourth plateau in the field-increasing branch and a sizable remanence when the field is decreased to zero. The newly observed plateau only appears at sufficiently low temperature and sufficiently large exchange interaction in the stacking direction. These observations reasonably reproduce low-temperatures measurements on the spin-chain compound Ca3Co2O6.

► We study magnetization curves in stacked triangular Ising antiferromagnet in a field.
► At low temperatures magnetization shows four plateaus in the field-increasing branch.
► The newly observed fourth plateau only appears at sufficiently low temperature.
► By decreasing the field back to zero we observe large hysteresis and remanence.
► These observations reasonably reproduce low temperatures measurements on Ca3Co2O6.