Mechanical and thermal properties of Tb2(MoO4)3 crystals

The mechanical and thermal properties of single crystal Tb2(MoO4)3 have been systematically studied. The result of microhardness measurement indicates that the crystal belongs to the soft materials category. The thermodynamic parameters obtained from DTA analysis were used for determining the type of liquid–solid interface during crystal growth. Negative thermal expansion along the c-axis was observed, and this behavior was attributed to the bent Tb–O–Mo bonds. The specific heat of the crystal was measured to be 0.122 cal g−1 K−1 at 293.15 K. The thermal conductivity of Tb2(MoO4)3 at room temperature was found to be smaller than that of representative ferroelectric LiNbO3.

► Tb2(MoO4)3 possesses a low hardness value and can be easily processed.
► The growth interface is a rough surface when Tb2(MoO4)3 is pulled from melt.
► The bent Tb–O–Mo bonds result in the negative thermal expansion along the c-axis.
► Abnormal behaviors are observed because of the phase transition.