Structural stability and compressibility behaviour of dialuminides of cerium and gadolinium under high pressure

High pressure x-ray diffraction experiments were done up to similar to 23 GPa on CeAl2 and up to similar to 16 GPa on GdAl2. Both the systems are stable in the cubic Laves phase up to the pressures investigated and show anomalous compressibility response as a function of pressure. In the case of GdAl2 the anomaly is quite subtle, however cerium compound shows a much more pronounced change between 2-6 GPa with no volume collapse. The compressibility behaviour is discussed in the Eight of changes occurring in the electronic structure. The extended range of stability of the MgCu2 type cubic Laves phase compounds under the action pressure is inferred from both these and our earlier studies.