The influence of pressure on the formation of U magnetic moments and mediation of exchange interactions are two principal aspects of the complex role of the 5f-ligand hybridization in magnetism of U intermetallics. Application of external pressure yields changes of interatomic distances, which are the crucial parameters controlling the hybridization. We report on pressure experiments with a 5f-electron ferromagnet UPtAl (TC=42.5 K, M s=1.4 μB/f.u. at ambient pressure). Application of hydrostatic pressure up to 1 GPa yields decrease of the spontaneous magnetization Ms with a rate dMs/dp=-0.027 μB/GPa, whereas TC increases (dTC/dp=2.5 K/GPa). Extension of the electrical resistivity measurements of UPtAl to pressures up to 22 GPa reveals that the initial increase of TC with pressure continues up to 6 GPa, where TC reaches the maximum value, and decreases with further increasing pressure. The drastic change of the R(T) curve at 17 GPa is presumably connected with suppression of ferromagnetism in UPtAl.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics