THERMAL-PROPERTIES OF INTRINSICALLY DISORDERED LINBO3 CRYSTALS AT LOW-TEMPERATURES

We have studied the specific heat and thermal conductivity of differen t LiNbO3 crystals between 0.4 K< T<100 K. In this material the amount of intrinsic disorder can be controlled by changing the stoichiometry. Although the disorder in the cation sublattices I:an exceed 6%, this material lacks the typical glasslike excitations observed in other dis ordered crystals. Our results agree with recent findings that suggest the presence of large random strains as essential to explain the appea rance of glassy properties in many crystalline materials.