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Hall effect in high-Tc superconductors with columnar defects
Physica C 235-240 (1994) 3141-3142
PHYSICA
North-Holland
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, d L . - G . Johansson e a C E A / D T A / D E C M , 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 d D e p a r t m e n t 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. I N T R O D U C T I O N The purpose of the present work is to verify directly t h a t 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 induced by high energy Pb ions irradiation. While the mixed-state longitudinal and Hall resistivities drastically decreased in magnitude after the irradiation, the Hall conductivity of both compounds remained unchanged. 2. E X P E R I M E N T A L
Experimental details can be found in our previous 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 resistivities were Ohmic in the range of temperatures and magnetic fields used ill this study. The samples were irradiated at room temperature 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. R E S U L T S
AND DISCUSSION
Analysis of the resistivity transitions of the YBa2Cu307 crystal containing columnar defects [3] revealed that the potential energy well increased 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 ) = 1 0 0 meV before irradiation and 250 meV after; U(T =90 K, H =2 T ) = 7 0 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 reversal of the Hall effect occurring in the vicinity of the transition t e m p e r a t u r e did not shift significantly. 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. SSDI0921-4534(94)02136-8
A.E Samoilov et al./Phvsica C 235 240 (/994) 3141 3142
3142
it,y is to decrease its magnitude. The lower telnperature is, the bigger is the ratio of Pxv before and after irradiation.
500 0
-500 7 E -1000 -1500 C ~ -2000
......... , ................................
-2500 ..........
[ ......
i ..........
..................
::o"~--i~-~=i:: Y~ua tJu
i ........
........ i .......... ::~........
..........i.......... i.........:t..........3.....z.~........... i......... i........
t~× - 3 0 0 0 -3500
.. i ......
80
82
84
i.,,
86
i...
88
i ......
90
i,,,:
92
94
96
T (K) Figure 1. Hall conductivity vs T ill YBa2Cu3()7 before (open symbols) and after (solid symbols) irradiation. Data for the Hall effect are divided by H because in the normal state, O-zu is proportional to H. Magnetic fields are 1 T, 2 T, and 4 T as indicated.
!'~"1'"'1"''1''' 1000 .r E L)
13 > 0 ~ xy ~
100
O'xy(
"7 10 o
1 ;
6O
| REFERENCES
O
0,1 , 70
80
tivity data and plotted the Hail conductivity as a function of temperature in Fig. 1 and 2. Fig. 1 represents data for YBa2Cu3OT, while data. for Tl-,Ba,_,CaCu~Os are depicted in Fig. 2. Wherever it. is possible t.o compare the data for tile mixed-state tlall conductivity before and after irradiation, one can see that the incorporation of the colunmar defects has not modified, within experimental accuracy, the behavior of a~u" This result which is valid independently on the sign of the Hall effect in the pinned region is the main finding of the work. In summary, we have shown that in both compounds, the incorporation of pinning centers does not change the mixed state Hall conductivity. This finding has essential consequences for the understanding of the vortex dynamics in superconductors. Our work proves experimentally that data on the Hail conductivity can be analyzed within the framework of theory such as the one based on the time-dependent Ginzburg-Landau (TDGL) equations, which does not include an effect of pinning but reveals intrinsic properties of the dynamics of the order parameter. An example of st, oh an analysis for Tl_,Ba2CaCu2Os can be found in I{ef. [2]. Also, it would be interesting to carry out thermomagnetic transport measurements in a superconducting sample before and after irradiation. In the pinned regime, the ratios N/p~.x and S/pzx (where N and 5' are the Nernst and Seebeck coefficients, respectively) have been predicted not to change by the incorporation of defects [4], similarly to the behavior of the tIall conductivity.
90 100 110 T (K)
20
1. 2.
Figure 2. Absolute values of the Hall conductivity in Tl2Ba2CaCu2Os at H = 2 T before (open symbols) and after (solid symbols) irradiation shown in a logarithmic scale.
We calculated ~rzy = P~'u/P~z using the resis-
3. 4.
V. M. \.;inokur ctal., Phys. Rev. Lett., 71, 1242 (1993). A. V. Samoilov, Phys. Rev. Lett., 71, 617 (1993); A. V. Samoilov, Z. G. Ivanov, and L.G..]ohansson, Phys. Rev. B 4 9 , 3667 (1994). A. Legris, F, Rullier-Albenque, and P. Lejay, Phys. Rev. B, 48, 10 634 (1993). A.V. Samoilov, Journal of Superconductivity, 7 (1994) (in: Proceedings of the Conference
on the Molecular and O~'ide Superconduclors, £ugcne, USA, 1993), to be published.
PHYSICA
North-Holland
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, d L . - G . Johansson e a C E A / D T A / D E C M , 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 d D e p a r t m e n t 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. I N T R O D U C T I O N The purpose of the present work is to verify directly t h a t 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 induced by high energy Pb ions irradiation. While the mixed-state longitudinal and Hall resistivities drastically decreased in magnitude after the irradiation, the Hall conductivity of both compounds remained unchanged. 2. E X P E R I M E N T A L
Experimental details can be found in our previous 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 resistivities were Ohmic in the range of temperatures and magnetic fields used ill this study. The samples were irradiated at room temperature 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. R E S U L T S
AND DISCUSSION
Analysis of the resistivity transitions of the YBa2Cu307 crystal containing columnar defects [3] revealed that the potential energy well increased 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 ) = 1 0 0 meV before irradiation and 250 meV after; U(T =90 K, H =2 T ) = 7 0 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 reversal of the Hall effect occurring in the vicinity of the transition t e m p e r a t u r e did not shift significantly. 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. SSDI0921-4534(94)02136-8
A.E Samoilov et al./Phvsica C 235 240 (/994) 3141 3142
3142
it,y is to decrease its magnitude. The lower telnperature is, the bigger is the ratio of Pxv before and after irradiation.
500 0
-500 7 E -1000 -1500 C ~ -2000
......... , ................................
-2500 ..........
[ ......
i ..........
..................
::o"~--i~-~=i:: Y~ua tJu
i ........
........ i .......... ::~........
..........i.......... i.........:t..........3.....z.~........... i......... i........
t~× - 3 0 0 0 -3500
.. i ......
80
82
84
i.,,
86
i...
88
i ......
90
i,,,:
92
94
96
T (K) Figure 1. Hall conductivity vs T ill YBa2Cu3()7 before (open symbols) and after (solid symbols) irradiation. Data for the Hall effect are divided by H because in the normal state, O-zu is proportional to H. Magnetic fields are 1 T, 2 T, and 4 T as indicated.
!'~"1'"'1"''1''' 1000 .r E L)
13 > 0 ~ xy ~
100
O'xy
"7 10 o
1 ;
6O
| REFERENCES
O
0,1 , 70
80
tivity data and plotted the Hail conductivity as a function of temperature in Fig. 1 and 2. Fig. 1 represents data for YBa2Cu3OT, while data. for Tl-,Ba,_,CaCu~Os are depicted in Fig. 2. Wherever it. is possible t.o compare the data for tile mixed-state tlall conductivity before and after irradiation, one can see that the incorporation of the colunmar defects has not modified, within experimental accuracy, the behavior of a~u" This result which is valid independently on the sign of the Hall effect in the pinned region is the main finding of the work. In summary, we have shown that in both compounds, the incorporation of pinning centers does not change the mixed state Hall conductivity. This finding has essential consequences for the understanding of the vortex dynamics in superconductors. Our work proves experimentally that data on the Hail conductivity can be analyzed within the framework of theory such as the one based on the time-dependent Ginzburg-Landau (TDGL) equations, which does not include an effect of pinning but reveals intrinsic properties of the dynamics of the order parameter. An example of st, oh an analysis for Tl_,Ba2CaCu2Os can be found in I{ef. [2]. Also, it would be interesting to carry out thermomagnetic transport measurements in a superconducting sample before and after irradiation. In the pinned regime, the ratios N/p~.x and S/pzx (where N and 5' are the Nernst and Seebeck coefficients, respectively) have been predicted not to change by the incorporation of defects [4], similarly to the behavior of the tIall conductivity.
90 100 110 T (K)
20
1. 2.
Figure 2. Absolute values of the Hall conductivity in Tl2Ba2CaCu2Os at H = 2 T before (open symbols) and after (solid symbols) irradiation shown in a logarithmic scale.
We calculated ~rzy = P~'u/P~z using the resis-
3. 4.
V. M. \.;inokur ctal., Phys. Rev. Lett., 71, 1242 (1993). A. V. Samoilov, Phys. Rev. Lett., 71, 617 (1993); A. V. Samoilov, Z. G. Ivanov, and L.G..]ohansson, Phys. Rev. B 4 9 , 3667 (1994). A. Legris, F, Rullier-Albenque, and P. Lejay, Phys. Rev. B, 48, 10 634 (1993). A.V. Samoilov, Journal of Superconductivity, 7 (1994) (in: Proceedings of the Conference
on the Molecular and O~'ide Superconduclors, £ugcne, USA, 1993), to be published.