[Sur les diagrammes de phase dʼUGe2]
Le mécanisme magnéto-élastique de lʼapparition dʼune instabilité du premier ordre à la transition de phase dans lʼétat ferromagnétique du supraconducteur ferromagnétique itinérant UGe2 est discuté. Une propriété remarquable de ce matériau est la chute abrupte de la température critique au voisinage dʼune pression de 14–15 kbar alors que la température de lʼinstabilité du premier ordre augmente fortement en comparaison de celle-ci. Cet effet qui conduit au changement de la transition du second au premier ordre est également determine par une augmentation de la chaleur spécifique dans un intervalle de températures correspondant au régime des fluctuations critiques. Après avoir effectué les calculs et les estimations nécessaires propres au composé UGe2, nous discutons lʼefficacité de ce mécanisme.
The magneto-elastic mechanism of development of the first order type instability at the phase transition to the ferromagnet state in itinerant ferromagnet-superconductor UGe2 is discussed. The particular property of this material is the precipitous drop of the critical temperature at pressure increase near 14–15 kbar that drastically increases the temperature of the first order instability in respect to the critical temperature. This effect leading to transformation of the second order type transition to the first order one is determined also by the specific heat increase in the temperature interval of the development of critical fluctuations. After performing the necessary calculations and estimations using the parameters characterizing the properties of UGe2 we argue the effectiveness of this mechanism.
Mot clés : Ferromagnétisme, Transitions de phase
Vladimir P. Mineev 1
@article{CRPHYS_2011__12_5-6_567_0,
author = {Vladimir P. Mineev},
title = {On the phase diagram of {UGe\protect\textsubscript{2}}},
journal = {Comptes Rendus. Physique},
pages = {567--572},
publisher = {Elsevier},
volume = {12},
number = {5-6},
year = {2011},
doi = {10.1016/j.crhy.2011.04.003},
language = {en},
}
Vladimir P. Mineev. On the phase diagram of UGe2. Comptes Rendus. Physique, Volume 12 (2011) no. 5-6, pp. 567-572. doi : 10.1016/j.crhy.2011.04.003. https://comptes-rendus.academie-sciences.fr/physique/articles/10.1016/j.crhy.2011.04.003/
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