Anomalous thermal expansion and magnetostriction of rare earth compounds under high pressure

The thermal expansion coefficients of Kondo compounds, CeBe13 and CeRh2Si2, and the magnetostriction of Tb0.3Dy0.7Fe2(Terfenol-D) have been measured at high pressure. By simple analysis using thermodynamical relation, it is found that the density of state at the Fermi level and the Grüneisen parameters ΓΓ of the Kondo compounds decrease rapidly with increasing pressure corresponding to the large pressure-induced enhancement of Kondo temperatures. An anomalous behaviour in the thermal expansion coefficients of CeRh2Si2 is observed at high pressure above TNTN. This anomaly is suggested as an origin of pressure-induced superconductivity. The giant magnetostriction (GMS) of Terfenol-D is found to be enhanced by applying hydrostatic pressure below 0.5 GPa but GMS decreases above it. These results are discussed briefly by comparing with the previous ones.