Physica C 235-240 (1994) 3141-3142 North-Holland PHYSICA Hall effect in high-Tc superconductors with columnar defects A. V. Samoilov, a* A. Legris, ~ F. Rullier-Albenque, ~ P. Lejay, b S. Bouffard, ¢ Z. G. Ivanov, Johansson e d L.-G. aCEA/DTA/DECM, Laboratoire des Solides Irradids, Ecole Polytechnique, 91128 Palaiseau, France bCentre de Recherches sur les Tr~s Basses Temperatures, Bo~te Postale 166X, 38042 Grenoble, France cCIRIL: Rue Claude Bloch - BP 5133 - 14040 Caen Cddex, France dDepartment of Physics, Chalmers University of Technology and University of Gothenburg, S-412 96 Gothenburg, Sweden eDepartment of Inorganic Chemistry, Chalmers University of Technology and University of Gothenburg, S-412 96 Gothenburg, Sweden We studied the Hall effect in the mixed state of a Tl2Ba2CaCu20s superconducting film and of a YBa2Cu3Or single crystal before and after irradiation with high energy Pb ions. The irradiation decreased the magnitude of the mixed state longitudinal and Hall resistivities, but the Hall conductivity remained unchanged, within experimental accuracy, after changing the pinning strength, in agreement with theory. 1. INTRODUCTION The purpose of the present work is to verify di- rectly that the Hall conductivity does not depend on the pinning strength as predicted in [1]. We enhanced pinning in a YBa2Cu307 single crystal and in c-axis oriented Tl~_Ba2CaCu2Os film by means of inclusions of the columnar defects in- duced by high energy Pb ions irradiation. While the mixed-state longitudinal and Hall resistivities drastically decreased in magnitude after the irra- diation, the Hall conductivity of both compounds remained unchanged. 2. EXPERIMENTAL Experimental details can be found in our pre- vious works [2], [3]. The magnetic field H was directed parallel to the c-axis, i.e. aligned with the tracks. Both the Hall and longitudinal resis- tivities were Ohmic in the range of temperatures and magnetic fields used ill this study. The samples were irradiated at room tempera- ture by 5.6 GeV Pb ions for the YBa-.Cu307 crys- *On leave from the P. L. Kapitza Institute for Physical Problems, ul. Kosygina 2, 117334 Moscow, Russia tal and by 1 GeV Pb ions for the Tl2Ba2CaCu2Os fihn. The irradiation fluences were 10 H ions/cm 2 for YBa~Cu307 and 5x101° ions/cm 2 for TI_~Sr2CaCu,,Os. 3. RESULTS AND DISCUSSION Analysis of the resistivity transitions of the YBa2Cu307 crystal containing columnar defects [3] revealed that the potential energy well in- creased by a factor of --,3.5 for H=I T and by a factor of ~2.5 for H=4 T. For the T12Ba2CaCu2Os film, we determined values of the activation energy U from the Arrhenius plots of the longitudinal resistivity (U(T =90 K, H =1 T)=100 meV before irradiation and 250 meV af- ter; U(T =90 K, H =2 T)=70 meV and 120 meV before and after irradiation, respectively). For rather small doses of irradiation we used in this work, the loci for the first sign rever- sal of the Hall effect occurring in the vicinity of the transition temperature did not shift signifi- cantly. In fact, this shift to lower temperatures did not exceed the reduction in Tc (,~0.3 K for both compounds). In the mixed state, the effect of irradiation-induced defects on the Hall resistiv- 0921-4534/94/$07.00 © 1994 - ElsevierScience B.V. All rights reserved. SSDI 0921-4534(94)02136-8