Theory of pressure effects and the correlated-electron behavior of uranium monochalcogenides
Hydrostatic pressure experiments provide a very sensitive way of probing the development of magnetic ordering in correlated-electron systems. With applied pressure, the Curie temperature (T(C)) for UTe increases from 104 K to a maximum of 181 K at 7.5 GPa and then decreases to 156 K at 17.5 GPa. This experimental behaviour is qualitatively what is expected on the basis of the theory of correlated-electron behaviour. Increasing pressure causes increased hybridisation which causes an increase of coupling between the moments associated with the relatively localised part of the f spectra density at each lattice site. However, as the pressure increases further, the loss of localised f spectra density caused by the increased merger with the non-f band density causes a decrease of ordered moment and hence a decrease in T(C). Calculations were performed quantifying the above picture for UTe. The pressure dependence of the lattice constant was calculated and is in good agreement with the experiment. T(C) was calculated using the correlated-electron theory for magnetic ordering. These results demonstrated the initial increase in T(C) resulting from increased hybridisation, as well as the reversal of this initial increase caused by the loss of localised f-density.
Bibliographic Reference: Paper presented: International Conference Actinides '93, Santa Fe (US), September 19-24, 1993
Availability: Available from (1) as Paper EN 37471 ORA
Record Number: 199311474 / Last updated on: 1994-11-28
Original language: en
Available languages: en