5 research outputs found
Low-Temperature Specific Heat of an Extreme-Type-II Superconductor at High Magnetic Fields
We present a detailed study of the quasiparticle contribution to the
low-temperature specific heat of an extreme type-II superconductor at high
magnetic fields. Within a T-matrix approximation for the self-energies in the
mixed state of a homogeneous superconductor, the electronic specific heat is a
linear function of temperature with a linear- coefficient
being a nonlinear function of magnetic field . In the range of magnetic
fields H\agt (0.15-0.2)H_{c2} where our theory is applicable, the calculated
closely resembles the experimental data for the borocarbide
superconductor YNiBC.Comment: 7 pages, 2 figures, to appear in Physical Review
Field-induced magnetic phases in the normal and superconducting states of ErNi<sub>2</sub>B<sub>2</sub>C
We present a comprehensive neutron-diffraction study of the magnetic structures of ErNi2B2C in the presence of a magnetic field applied along [010], [110], or [001]. In zero field, the antiferromagnetic structure is transversely polarized with Qapproximate to0.55a* and the moments along the b direction. At the lowest temperatures, the modulation is close to a square wave, and transitions of Q between different commensurable values are observed when varying the field. The commensurable structures are analyzed in terms of a detailed mean-field model. Experimentally, the minority domain shows no hysteresis and stays stable up to a field close to the upper critical field of superconductivity, when the field is applied along [010]. Except for this possible effect, the influences of the superconducting electrons on the magnetic structures are not directly visible. Another peculiarity is that Q rotates by a small, but clearly detectable, angle of about 0.5degrees away from the [100] and the field direction, when the field is applied along [110] and is approximately equal to or larger than the upper critical field.This article is published as Jensen, A., K. Nørgaard Toft, A. B. Abrahamsen, D. F. McMorrow, M. R. Eskildsen, N. H. Andersen, J. Jensen et al. "Field-induced magnetic phases in the normal and superconducting states of ErNi 2 B 2 C." Physical Review B 69, no. 10 (2004): 104527.
DOI: 10.1103/PhysRevB.69.104527.
Copyright 2004 American Physical Society.
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