Heat capacity and lattice dynamics of yttrium diboride in the temperature range 5–300 K

This paper reports an experimental study of the heat capacity and crystal lattice parameters of a polycrystalline sample of yttrium diboride prepared by high-temperature synthesis from elements. The electronic and lattice contributions to the heat capacity are isolated. The temperature dependences of the characteristic temperature, the linear thermal expansion coefficients αa(T) and αc(T), the bulk thermal expansion coefficient β(T), and the Grüneisen coefficient are calculated. A region of negative values of αc(T) and β(T) is revealed. Anharmonicity is found to exert only a minor effect on the YB2 lattice dynamics over a larger part of the temperature range covered.