EFFECTS OF ALLOYING AND PRESSURE ON METAMAGNETISM OF UCOAL

Doping by other d-metals in the Co sublattice and/or application of ex ternal pressure influences strongly the magnetic properties of 5f-band metamagnet UCoAl. Already 1-2% of Ru or Fe stabilise ferromagnetism, while the doping by Ni as well as the external pressure suppress the m etamagnetism. The main role of the observed alloying and pressure effe cts can be attributed to the involvement of the 5f-ligand hybridisatio n in both the U 5f-moment formation and the 5f-5f exchange interaction s. In many aspects UCoAl shows strong similarities to the 3d band meta magnets CoS2, YCo2 and LuCo2, which suggests an essentially same origi n of field-induced phenomena in the both classes of materials.