Abstract.
Based on field-cooled dc-magnetization measurements in a SQUID magnetometer with carefully controlled magnetic-field profiles, we present evidence that diamagnetism is missing in the superconducting state (T < 50 K) of the (weakly) ferromagnetic (TM ≈130 K) superconductor RuSr2GdCu2O8 (Ru1212). Nevertheless, taking into account the granular nature of the samples investigated so far, this cannot be taken as evidence for the lack of a Meissner state or bulk superconductivity. It is shown that for low applied magnetic fields a vortex state most probably involves the intergrain area (area between the grains) rather than the individual grains (bulk Ru1212). Furthermore, the wide superconducting transition of Ru1212 (Tc,onset = Tc ≈48 K, Ts(R = 0) = Ts = 32 K) realized in resistance measurements in zero applied magnetic field can be readily understood as the effect of resistive grain contacts and is not necessarily related to the movement of spontaneously induced vortices in bulk Ru1212, as it has been suggested previously. A comparison of the low-temperature specific heat of Sr2GdRuO6 (Sr2116), the precursor for the preparation of Ru1212 and thus a possible impurity phase, with previously reported data for Ru1212 shows that it is unlikely that Sr2116 is responsible for the specific-heat features attributed to the superconductivity of Ru1212 and supports the existence of a bulk superconducting state in the latter compound.
Similar content being viewed by others
References
L. Bauernfeind, Supraleitung und Magnetismus in rutheniumhaltigen Kupraten, Ph.D. thesis, University of Bayreuth, 1998
J.W. Lynn, B. Keimer, C. Ulrich, C. Bernhard, J.L. Tallon, Phys. Rev. B 61, 14964(R) (2000)
K.I. Kumagai, S. Takada, Y. Furukawa, Phys. Rev. B 63, 180509(R) (2001)
A. Butera, A. Fainstein, E. Winkler, J. Tallon, Phys. Rev. B 63, 054442 (2001)
A.C. McLaughlin, W. Zhou, J.P. Attfield, A.N. Fitch, J.L. Tallon, Phys. Rev. B 60, 7512 (1999)
C. Bernhard, J.L. Tallon, E. Brücher, R.K. Kremer, Phys. Rev. B 61, 14960(R) (2000)
Y.Y. Xue, R.L. Meng, J. Cmaidalka, B. Lorenz, L.M. Desaneti, A.K. Heilman, C.W. Chu, Physica C 341–348, 459 (2000)
C.Y. Yang, B.C. Chang, H.C. Ku, Y.Y. Hsu, Phys. Rev. B 72, 174508 (2005)
C.T. Lin, B. Liang, C. Ulrich, C. Bernard, Physica C 354-365, 373 (2001)
C.W. Chu, Y.Y. Xue, S. Tsui, J. Cmaidalka, A.K. Heilman, B. Lorenz, R.L. Meng, Physica C 335, 231 (2000)
J.L. Tallon, J.W. Loram, G.V.M. Williams, C. Bernhard, Phys. Rev. B 61, 6471(R) (2000)
Chen Shaou, H.F. Braun, T.P. Papageorgiou, Journal of Alloys and Compounds 351, 7 (2003)
T.P. Papageorgiou, T. Herrmannsdörfer, R. Dinnebier, T. Mai, T. Ernst, M. Wunschel, H.F. Braun, Physica C 377, 383 (2002)
J.C. Lashley, M.F. Hundley, A. Migliori, J.L. Sarrao, P.G. Pagliuso, T.W. Darling, M. Jaime, J.C. Cooley, W.L. Hults, L. Morales, D.J. Thoma, J.L. Smith, J. Boerio-Goates, B.F. Woodfield, G.R. Stewart, R.A. Fisher, N.E. Phillips, Cryogenics 43, 369 (2003)
T. Herrmannsdörfer, H. Krug, F. Pobell, S. Zherlitsyn, H. Eschrig, J. Freudenberger, K.H. Müller, L. Schultz, J. Low Temp. Phys. 133, 41 (2003)
http://www.fz-rossendorf.de/HLD
P.W. Klamut, B. Dabrowski, M. Maxwell, J. Mais, O. Chmaissem, R. Kruk, R. Kmiec, C.W. Kimball, Physica C 341–348, 455 (2000)
C. Artini, M.M. Carnasciali, G.A. Costa, M. Ferretti, M.R. Cimberle, M. Putti, R. Masini, Physica C 377, 431 (2002)
M.R. Cimberle, R. Masini, C. Ferdeghini, C. Artini, G. Costa, Supercond. Sci. Technol. 16, 726 (2003)
T.P. Papageorgiou, H.F. Braun, T. Herrmannsdörfer, Phys. Rev. B 66, 104509 (2002)
T.P. Papageorgiou, L. Bauernfeind, H.F. Braun, J. Low Temp. Phys. 131, 129 (2003)
T.P. Papageorgiou, H.F. Braun, T. Görlach, M. Uhlarz, H.v. Löhneysen, Phys. Rev. B 68, 144518 (2003)
T.P. Papageorgiou, H.F. Braun, SQUID Magnetometry of Superconducting Samples: A Practical Guide, in: Trends in Superconductivity Research, edited by P.S. Lewis (Nova Science Publishers, Inc., 2004), p. 39
B. Lorenz, Y.Y. Xue, R.L. Meng, C.W. Chu, Phys. Rev. B 65, 174503 (2002)
J.R. Clem, Physica C 153–155, 50 (1988)
T. Nachtrab, D. Koelle, R. Kleiner, C. Bernhard, C.T. Lin, Phys. Rev. Lett. 92, 117001 (2004)
Y. Tokunaga, H. Kotegawa, K. Ishida, Y. Kitaoka, H. Takagiwa, J. Akimitsu, Phys. Rev. Lett. 86, 5767 (2001)
X.H. Chen, Z. Sun, K.Q. Wang, S.Y. Li, Y.M. Xiong, M. Yu, L.Z. Cao, Phys. Rev. B 63, 064506 (2001)
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Papageorgiou, T., Casini, E., Braun, H. et al. Magnetization, vortex state and specific heat in the superconducting state of RuSr2GdCu2O8 . Eur. Phys. J. B 52, 383–388 (2006). https://doi.org/10.1140/epjb/e2006-00317-4
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1140/epjb/e2006-00317-4