Effect of pressure on the tiny antiferro-magnetic moment in URu2Si2

Citation
A. Tsuruta et al., Effect of pressure on the tiny antiferro-magnetic moment in URu2Si2, J PHYS CH S, 62(1-2), 2001, pp. 301-304
Citations number
22
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
ISSN journal
0022-3697 → ACNP
Volume
62
Issue
1-2
Year of publication
2001
Pages
301 - 304
Database
ISI
SICI code
0022-3697(200101/02)62:1-2<301:EOPOTT>2.0.ZU;2-5
Abstract
We propose a scenario to explain the anomalous pressure dependence of the a ntiferro-magnetic moment observed in URu2Si2, the steep change from tiny to large moments at lower pressures (P < P-c = 15 GPa) and the gradual change of large moment at higher pressures (P > P-c). We speculate that at ambien t pressure the ionic ground state of U is non-magnetic quadrupolar doubler Gamma (5) with (5f)(2), which is hybridized with the excited state of magne tic dipolar doubler Gamma (7) with (5f)(1) via conduction electrons due to the Kondo effect with respect to quadrupolar degrees of freedom. By decreas ing temperature T, quadrupolar order sets in at a certain temperature T, an d then octupolar order sets in additionally at a certain lower temperature T-1 < T-o leading to a tiny magnetic moment induced through the weak hybrid ization of the magnetic excited state to the nonmagnetic ground state. By i ncreasing P, the hybridization energy increases steeply and so does the ind uced magnetic moment at P < P-c. On the other hand, at P > P-c, the charact er of the ground state of uranium ions changes to be magnetic somehow. Then the magnetic order with large magnetic moment manifests itself at T < T-o. This scenario is confirmed by using a two-channel Anderson lattice model. (C) 2000 Elsevier Science Ltd, All rights reserved.