Comment on "superconducting anisotropy and evidence for intrinsic pinning in single crystalline MgB2"

Physical Review B - Condensed Matter and Materials Physics

Volumn 70, Issue 22, 2004, Pages

  Angst, M ^a,d   Puzniak, R ^b   Wisniewski, A ^b   Roos, J ^c   Keller, H ^c   Karpinski, J ^a  

^a ETH ZURICH   (Switzerland)

^b INSTITUTE OF PHYSICS   (Poland)

^c UNIVERSITY OF ZURICH   (Switzerland)

^d IOWA STATE UNIVERSITY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

BORON DERIVATIVE; MAGNESIUM DERIVATIVE;

ANISOTROPY; CALCULATION; CORRELATION ANALYSIS; CRYSTAL; ELECTRIC FIELD; HYPOTHESIS; MEASUREMENT; PARAMETER; REVIEW; SUPERCONDUCTOR; TEMPERATURE DEPENDENCE; TORQUE;

EID: 13944249260     PISSN: 10980121     EISSN: 1550235X     Source Type: Journal    
DOI: 10.1103/PhysRevB.70.226501     Document Type: Review

References (18)

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3. M. Angst, R. Puzniak, A. Wisniewski, J. Jun, S. M. Kazakov, J. Karpinski, J. Roos, and H. Keller, Phys. Rev. Lett. 88, 167004 (2002); see also M. Angst, R. Puzniak, A. Wisniewski, J. Roos, H. Keller, P. Miranović, J. Jun, S. M. Kazakov, and J. Karpinski, Physica C 385, 143 (2003).
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12. 2, due to the effects of "two band superconductivity." For a discussion of this point, which is outside of the scope of this Comment, see, for example, M. Angst and R. Puzniak, in Focus on Superconductivity Research 2003, edited by B. P. Martines (Nova Publishers, New York, 2004); M. Angst, D. Di Castro, D. G. Eschenko, R. Khasanov, S. Kohout, I. M. Savic, A. Shengelaya, S. L. Bud'ko, P. C. Canfield, J. Jun, J. Karpinski, S. M. Kazakov, R. A. Ribeiro, and H. Keller, cond-mat/0305048, Phys. Rev. B (to be published).
13. 2, due to the effects of "two band superconductivity." For a discussion of this point, which is outside of the scope of this Comment, see, for example, M. Angst and R. Puzniak, in Focus on Superconductivity Research 2003, edited by B. P. Martines (Nova Publishers, New York, 2004); M. Angst, D. Di Castro, D. G. Eschenko, R. Khasanov, S. Kohout, I. M. Savic, A. Shengelaya, S. L. Bud'ko, P. C. Canfield, J. Jun, J. Karpinski, S. M. Kazakov, R. A. Ribeiro, and H. Keller, cond-mat/0305048, Phys. Rev. B (to be published).
14. The small perpendicular ac magnetic field disturbs ("shakes") the vortices, leading to a fast (exponential) relaxation into equilibrium. See Ref. 12 for technical details. Note that the "shaking" procedure employed here is different from performing minor hysteresis loops. It was often pointed out that a demagnetization by repeating minor loops can lead to some residual magnetization in the material. However, it is not the case when "shaking" by a perpendicular ac field, which leads to the speed-up of the relaxation of the vortices to their equilibrium positions. A detailed theoretical explanation of this speed-up of the relaxation to the equilibrium by the shaking procedure was recently given by E. H. Brandt and G. P. Mikitik, Phys. Rev. Lett. 89, 027002 (2002); G. P. Mikitik and E. H. Brandt, Phys. Rev. B 67, 104511 (2003).
15. The small perpendicular ac magnetic field disturbs ("shakes") the vortices, leading to a fast (exponential) relaxation into equilibrium. See Ref. 12 for technical details. Note that the "shaking" procedure employed here is different from performing minor hysteresis loops. It was often pointed out that a demagnetization by repeating minor loops can lead to some residual magnetization in the material. However, it is not the case when "shaking" by a perpendicular ac field, which leads to the speed-up of the relaxation of the vortices to their equilibrium positions. A detailed theoretical explanation of this speed-up of the relaxation to the equilibrium by the shaking procedure was recently given by E. H. Brandt and G. P. Mikitik, Phys. Rev. Lett. 89, 027002 (2002); G. P. Mikitik and E. H. Brandt, Phys. Rev. B 67, 104511 (2003).
16. M. Willemin, C. Rossel, J. Hofer, H. Keller, A. Erb, and E. Walker, Phys. Rev. B 58, R5940 (1998).
17. Sample A of Ref. 2.
18. Note that the angle values in the insets of Fig. 5 correspond to the angle between H and the ab plane.