STRUCTURE AND THERMAL-EXPANSION OF LIV2O4 - CORRELATION BETWEEN STRUCTURE AND HEAVY-FERMION BEHAVIOR

The structural properties ol the heavy fermion (HF) transition metal o xide LiV2O4 have been studied as a function of temperature T from 4 to 295 K. Upon cooling from 295 K the lattice parameter a contracts grad ually to become nearly constant between 65 and 20 K and then decreases again below 20 K. The downturn in a(T) below 20 K correlates with the crossover from local moment to HF behavior. The thermal expansion is found to depend predominantly on the interatomic Li-O bonds while V-O bond lengths change only slightly. The electronic Gruneisen parameter at 7 K is inferred to be large (similar to 25), similar to low:T value s of some f-electron HF compounds.