Peak effect in CeRu₂: History dependence and supercooling

We present experimental results on single crystal CeRu₂ showing that the extent of the history dependence of peak effect depends on the path followed in the space of field (H) and temperature (T). The (H,T) regime over which the history effect is observed is larger if the vortex lattice is prepared by lowering T from above T_C in constant H, i.e., by field cooling. We compare this history effect with the very recently reported history dependence of peak effect in detwinned single crystals of YBaCuO and 2H-NbSe₂, highlighting the similarities and differences. We discuss the possibility of a first-order vortex solid-solid transition in CeRu₂ within the realm of recent theoretical developments in the field of vortex matter.