First-Order Transition in the Magnetic Vortex Matter in Superconducting MgB2 Tuned by Disorder

Thierry Klein (1) , R. Marlaud , C. Marcenat (2) , Hervé Cercellier (1) , M. Konczykowski (3) , C. J. van Der Beek (3) , V. Mosser (4) , H. S. Lee (5) , S. I. Lee (5)

1 NEEL - MagSup - Magnétisme et Supraconductivité
2 SPSMS - UMR 9001 - Service de Physique Statistique, Magnétisme et Supraconductivité
3 LSI - Laboratoire des Solides Irradiés - Irradiated Solids Laboratory
4 ITRON
5 NVCRICS

The field-driven transition from an ordered Bragg glass to a disordered vortex phase in singlecrystalline MgB2 is tuned by an increasing density of point defects, introduced by electron irradiation. The discontinuity observed in magnetization attests to the first-order nature of the transition. The temperature and defect density dependences of the transition field point to vortex pinning mediated by fluctuations in the quasiparticle mean free path, and reveal the mechanism of the transition in the absence of complicating factors such as layeredness or thermal fluctuations.

Mots clés: supraconductivité

Domaines: Supraconductivité [cond-mat.supr-con]

Thierry Klein, R. Marlaud, C. Marcenat, Hervé Cercellier, M. Konczykowski, et al.. First-Order Transition in the Magnetic Vortex Matter in Superconducting MgB2 Tuned by Disorder. Physical Review Letters, 2010, 105, pp.047001. ⟨10.1103/PhysRevLett.105.047001⟩. ⟨hal-00957170⟩