Evidence of a high-temperature dipole-glass phase inK2CrO4

Abstract

Dielectric measurements on single crystals of ${\mathrm{K}}_2$ ${\mathrm{CrO}}_4$ are reported for temperatures in the vicinity of the α-β transition ($T_c$≃960 K) and frequencies in the range ${10}^4$–${10}^6$ Hz. The dielectric constant along the pseudohexagonal axis shows a weak anomaly at $T_c$, and pronounced frequency-dependent cusps at slightly higher temperatures. The results are interpreted in terms of a possible dipole-glass state arising from randomness introduced by the presence of vacancies.