Damping of de Haas-van Alphen oscillations and vortex-lattice disorder in the peak-effect region of extreme type-II borocarbide superconductors

A. Maniv, T. Maniv, V. Zhuravlev, B. Bergk, J. Wosnitza, A. Köhler, G. Behr, P. C. Canfield, and J. E. Sonier

Phys. Rev. B 83, 104505 – Published 14 March 2011

Abstract

The study of magnetic quantum oscillations in the superconducting state is of fundamental importance for understanding the nature of superconductivity under high magnetic fields. However, although studied for more than three decades, this phenomenon poses several basic questions that still defy satisfactory answers. A key controversial issue concerns the additional damping observed in the vortex state of many strong type-II superconductors. Here, we show results of $μ$ SR, dHvA, and superconducting quantum interference device magnetization measurements on borocarbide superconductors, initially aimed at investigating the “phase-smearing” effect due to inhomogeneous field broadening. It is found, however, that a sharp drop observed in the dHvA amplitude just below $H_{c 2}$ is correlated with enhanced disorder of the vortex lattice in the peak-effect region, where the phase-smearing effect is negligible. It is concluded that quasiparticle scattering by the pair potential is significantly enhanced due to vortex-lattice disorder, thus generating additional damping in the dHvA amplitude.

Received 8 December 2010

DOI:https://doi.org/10.1103/PhysRevB.83.104505

Authors & Affiliations

A. Maniv¹, T. Maniv^2,*, V. Zhuravlev², B. Bergk³, J. Wosnitza³, A. Köhler⁴, G. Behr⁴, P. C. Canfield⁵, and J. E. Sonier^6,7

¹NRCN, PO Box 9001, Beer Sheva, IL-84190, Israel
²Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa IL-32000, Israel
³Hochfeld-Magnetlabor Dresden (HLD), Helmholtz-Zentrum Dresden-Rossendorf, DE-01314 Dresden, Germany
⁴Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden, DE-01171 Dresden, Germany
⁵Ames Laboratory and Department of Physics, Iowa State University, Ames, Iowa 50011, USA
⁶Department of Physics, Simon Fraser University, Burnaby, British Colombia, Canada V6T 1Z1
⁷Canadian Institute for Advanced Research, Toronto, Ontario, Canada

^*maniv@tx.technion.ac.il

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Vol. 83, Iss. 10 — 1 March 2011

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Images

Figure 1
(a) dHvA oscillation signals for upward and downward field sweeps, respectively, measured on LuNi $_{2}$ B $_{2}$ C after background subtraction, and (b) the corresponding Dingle plots (triangles and circles, respectively). The gray oscillatory lines in (a) represent the extrapolated dHvA signal, based on the normal-state Lifshitz-Kosevich formula, whereas the solid straight line in (b) is the corresponding Dingle plot. The total magnetization for both field sweeps (solid curves) is also shown in (b). The dashed-dotted line in (b) represents the result of a calculation based on the random vortex distribution model with the zero-field order parameter $Δ_{0} = 4$ meV and mean field $H_{c 2} = 8$ T. Measurements were done at 0.5 K.Reuse & Permissions
Figure 2
(Upper panel) Probability field-distribution lines $P (B)$ , for LuNi $_{2}$ B $_{2}$ C (solid lines) at different external magnetic fields, derived by deconvoluting the FFTs (open symbols) of the $μ$ SR signals. Measurements at $H =$ 3, 4, 5, and 6 T were done after field cooling to 2.3 K at 3 T, whereas at $H =$ 5.3 and 5.6 T were performed after degaussing at 2.7 K. The lines were displaced vertically for clarity and horizontally for comparison. The reference data used in the deconvolution were measured on the same sample above $T_{c}$ at $T = 20$ K. The shoulder seen on the 3-T FFT curve around 25 G is due to muons that missed the SC sample. (Lower panel) Field dependence of the skewness parameter $α$ (see text) as calculated from the field distributions shown in the upper panel. The line connecting the data points is a guide to the eyes.Reuse & Permissions
Figure 3
Field dependence of the longitudinal magnetic moment LuNi $_{2}$ B $_{2}$ C around the PE region obtained by SQUID magnetization measurements at $T = 2.3$ K (upper panel), and the corresponding field dependence of the $μ$ SR field distribution width (lower panel) calculated from the data shown in Fig. 2. The line connecting the data points is a guide to the eyes.Reuse & Permissions
Figure 4
(a) Field dependence of the longitudinal magnetic moment of YNi $_{2}$ B $_{2}$ C near the PE region obtained by SQUID magnetization measurements for the indicated cooldown conditions at 2.1 and 3 K. (b) Field dependence of the $μ$ SR field distribution width calculated from the data obtained at 2.1 and 3 K.Reuse & Permissions
Figure 5
Temperature dependence of the field distribution width, measured after 3 T (squares) and 0.5 T (circles) cooldowns. For each cooldown, the measurements were done at a certain field, i.e., 4.5 T for the 0.5 T cooldown and 3 T for the 3 T cooldown.Reuse & Permissions

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