Analysis of the volume dependence of Gruneisen parameter for gamma-Fe2O3 nanomaterial

The volume dependence of Gruneisen parameter of gamma-Fe2O3 nanomaterial has been investigated using the results obtained from the Barton-Stacey formula and three different equations of state viz. the Birch-Murnaghan equation, Brennan-Stacey equation and the Vinet-Rydberg equation of state. Values of the ratio of Gruneisen parameter and volume compression have been determined using the results for pressure, bulk modulus and pressure derivative of bulk modulus for gamma-Fe2O3 at different volumes. The Brennan-Stacey equation of state is based on the assumption that the ratio of the Gruneisen parameter to volume compression remains constant. It has been found that the ratio of Gruneisen parameter and volume does not remain constant with the change in volume compression for the Birch-Murnaghan and the Vinet- Rydberg equations of state.