[Interaction entre le magnétisme et la supraconductivité dans URhGe]
Une transition de phase métamagnétique se produit dans le composé ferromagnétique itinérant URhGe lorsqu'un champ magnétique approximativement égal à 12 Tesla est appliqué le long de l'axe de faible anisotropie, dans le plan perpendiculaire à la direction de l'aimantation spontanée. Cette transition s'accompagne d'un maximum de la résistivité dans l'état normal et, à basse température, un état supraconducteur réentrant apparaît sous un champ magnétique compris entre 8 et 12 Tesla [F. Lévy et al., Science 309 (2005) 1343].
Nous discutons la transition de rotation de l'aimantation, ainsi que les différentes symétries de la phase supraconductrice qui coexiste avec l'état ferromagnétique jusqu'à 2 Tesla, puis réapparaît sous des champs proches de la transition metamagnétique.
Le groupe de symétrie cristalline de URhGe est non symorphique. Un ordre antiferromagnétique avec les moments magnétiques des paires des atomes d'Uranium orientés le long de la direction a est donc possible. L'amplitude du paramètre d'ordre antiferromagnétique faible augmente au dessus de la transition dans l'état supraconducteur grâce au magnétisme spontané des paires de Cooper.
The magnetization rotation transition occurs in the itinerant ferromagnet URhGe when the field about 12 Tesla is applied in direction perpendicular to spontaneous magnetization in the plane of the smallest magnetic anisotropy energy. The transition is accompanied by the maximum of resistivity in the normal state and by re-entrance of superconductivity at lower temperatures in the field interval between 8 and 13 Tesla [F. Lévy et al., Science 309 (2005) 1343].
We discuss the magnetization orientation transition and the modification of triplet pairing superconducting state coexisting with ferromagnetism up to the fields about 2 Tesla and then reappearing in the broad vicinity of the transition.
The nonsymmorphic space group crystal symmetry of ferromagnetic URhGe allows the existence of antiferromagnetic ordering of magnetic moments of pairs of uranium atoms along the a-axis. We show that the amplitude of this weak antiferromagnetic ordering increases below the phase transition into superconducting state due to Cooper pairs spontaneous magnetism.
Mot clés : Supraconductivité non conventionnelle, Ferromagnétisme
Vladimir P. Mineev 1
@article{CRPHYS_2006__7_1_35_0, author = {Vladimir P. Mineev}, title = {Interplay between magnetism and superconductivity in {URhGe}}, journal = {Comptes Rendus. Physique}, pages = {35--41}, publisher = {Elsevier}, volume = {7}, number = {1}, year = {2006}, doi = {10.1016/j.crhy.2005.11.006}, language = {en}, }
Vladimir P. Mineev. Interplay between magnetism and superconductivity in URhGe. Comptes Rendus. Physique, Volume 7 (2006) no. 1, pp. 35-41. doi : 10.1016/j.crhy.2005.11.006. https://comptes-rendus.academie-sciences.fr/physique/articles/10.1016/j.crhy.2005.11.006/
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The magnetic moment in domains of URhGe is screened incompletely (see the discussion at the end of Section 3).
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