Disorder-induced Phase Transition of Vortex Matter in MgB2

Abstract

Measurements of single crystalline MgB2 with torque magnetometry in fields up to 90 kOe reveal a sharp peak in the irreversible torque at about 0.85 Hc2. In the region between peak onset and maximum, pronounced history effects occur. Angle and temperature dependence of the characteristic peak fields track those of Hc2. The features observed suggest that the peak marks a disorder-induced phase transition of vortex matter between a quasi-ordered Bragg glass and a highly-disordered glass.

4 pages, 4 figures; minor changes, Phys. Rev. B in print

References in corpus (11)

• Two-Band Superconductivity in MgB2
• Phenomenological two-gap model for the specific heat of MgB_2
• Temperature and field dependence of the anisotropy of MgB2
• Inverse melting of the vortex lattice
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• Mixed state properties of superconducting MgB2 single crystals
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• Temperature dependence and anisotropy of the bulk upper critical field H_c2 of MgB_2
• Peak effect in single crystal MgB${}_2$ superconductor for $\mathbf{H}\parallel c$-axis
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• Critical Currents and Order-Disorder Phase Transition in the Vortex States of YBa2Cu4O8 with Chemically Introduced Disorder

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• Thermally-activated current transport in MgB_2 films
• Reversible magnetization of MgB2 single crystals with a two-gap nature
• Phase transition between the Bragg Glass and a disordered Phase in Nb3Sn, detected by 3rd harmonics of the AC magnetic susceptibility
• Magnetic field dependence of vortex activation energy: a comparison between MgB2, NbSe2 and Bi2Sr2Ca2Cu3O10 superconductors
• Effects of proton irradiation and ageing on the superconducting properties of single crystalline and polycrystalline MgB2
• Evolution of vortex pinning in the FeSe${}_{1-x}$S${}_x$ system
• Anomalous peak effect in iron-based superconductors Ba${}_{1-x}$K${}_x$Fe${}_2$As${}_2$ ($x\approx$ 0.69 and 0.76) for magnetic-field directions close to the $ab$ plane and its possible relation to the spin paramagnetic effect