Experimental equations of state for calcium, strontium, and barium metals to 20 kbar from 4 to 295 K

Piston-displacement measurements have been used to determine the equations of state of high-purity calcium and strontium (both fcc) and barium (bcc) metals to 20 kbar from 4 to 295 K. For each metal, the results have roughly 1% accuracy for the P=0 bulk modulus at 295 K and for the total volume change with pressure. The results also give the change with temperature of both the P=0 volume and the isothermal bulk modulus for these metals. While the bulk moduli for calcium and strontium are dependent only on the volume, those for barium show a significant temperature dependence with decreasing volume. Specifically, the bulk modulus for barium at 10 kbar is roughly 3% smaller at 295 K than would be predicted from the 0-K value at the same volume. Differences between the pressure-volume relations for bare samples and for those which were jacketed with indium metal are not understood.