Thermal Hystersis in Magnetic Phases of Solid Oxygen

Measurements of the dielectric susceptibility of solid oxygen have been carried out in the temperature range 4.2$<$T$<$54 K. Relatively large hysteresis effects $(\sim 0.4\%)$ have been observed for the dielectric response in the $\alpha$ and $\beta$ phases on thermal cycling below 44 K. The temperature for the transition between the two-sublattice antiferromagnetic $\alpha$ phase and the frustrated quasi-helical $\beta$ phase is observed to be independent of the thermal cycles. The areas of the thermal hysteresis scale with the extent of the thermal excursion in the frustrated $\alpha$ phase.