A low temperature phase transition in potassium perchlorate (KClO4)?

The dielec. behavior of $KClO_4$ was studied at low temp. to liq. He temp. and confirmed by DSC. The dielec. and thermal studies of $KClO_4$ at low-temp. indicates the presence of a low-temp. structure transition with considerable thermal hysteresis (.apprx.$20^0$). The intensity of the dielec. peak reduces considerably during successive thermal cycling. The dielec. anomaly might be due to a disorder in the orientation of the $ClO_4$ groups in the as-grown crystals. This disorder can contribute to the dielec. anomaly in the crystal. The disorder in the $ClO_4$ orientations in addn. to making a contribution directly, can also through the ionic polarization play a role in the anomaly. By thermal cycling this disorder possibly gets minimized and the structure acquires the spatial ordering corresponding to the space group Pnma and the dielec. anomaly slowly decrease