THERMAL PROPERTIES OF INTRINSICALLY DISORDERED LINBO3 CRYSTALS AT LOW TEMPERATURES

We have studied the specific heat and thermal conductivity of different ${\mathrm{LiNbO}}_{3}$ crystals between $0.4\mathrm{K}lTl100\phantom{\rule{0ex}{0ex}}\mathrm{K}$. In this material the amount of intrinsic disorder can be controlled by changing the stoichiometry. Although the disorder in the cation sublattices can exceed 6%, this material lacks the typical glasslike excitations observed in other disordered crystals. Our results agree with recent findings that suggest the presence of large random strains as essential to explain the appearance of glassy properties in many crystalline materials.