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Mn substitution in 2223 Bi-based HTSC
Physica B 321 (2002) 298–300
The effect of Cu/Mn substitution in 2223 Bi-based HTSC A. Sidorenkoa,b,*, E.-W. Scheidta, F. Haidera, M. Klemma, S. Horna, L. Konopkob, R. Tidecksa a
Institut fur . Physik, Universitat . Augsburg, D-86159 Augsburg, Germany b Institute of Applied Physics, MD-2028 Kishinev, Moldova
Abstract The effect of partial Cu by Mn substitution in the 2223 high-Tc superconductor (Bi0.8Pb0.2)2(Sr0.9Ba0.1)2Ca2(Cu1xMnx)3O10+y with Mn concentration in the range 0oxo0:3 was studied by resistivity, DC susceptibility, XRD, EDX, and neutron diffraction measurements. The EDX analysis confirmed the Mn presence inside the grains in Mndoped samples. Neutron diffraction measurements show no evidence for magnetic ordering of Mn for 20 KoTo300 K: The critical temperature, Tconset ; of the samples, determined from the temperature dependence of the electrical resistivity, RðTÞ; and from the diamagnetic response, MðTÞ; show no changes of Tconset ¼ 108 K for a wide Mn concentration range, 0oxo0:2: A substitution of Cu by Mn in the Cu–O pyramids and not in the Cu–O sheets of the 2223 lattice may be the reason of the Mn concentration independence of Tconset : r 2002 Elsevier Science B.V. All rights reserved. Keywords: Superconductivity; High-Tc ; Bi-2223
1. Introduction Bi-based cuprate superconductors represented by the series Bi2Sr2Can1CunO2n+4 with n ¼ 123 have some important properties for basic science and applications: (1) a highly waved modulated crystal structure; (2) highly anisotropic twodimensional superconductivity; (3) the possibility of obtaining high grain alignment even in polycrystalline samples. In order to obtain information about the mechanism of the formation of modulated structures, as well as on the relation between modulation and superconductivity, the effects of *Corresponding author. Institut fur . Physik, Universit.at Augsburg, D-86159 Augsburg, Germany. Fax: +49-8215983225. E-mail address: [email protected] (A. Sidorenko).
partial substitution of Bi- or Cu-sites with other cations have been intensively studied [1]. It was found that partial Sr substitution by Ba leads to a reduction of the modulation period and to an increase of Tconset ; while partial Bi substitution by Pb promotes and stabilizes the high-Tc 2223-phase [2]. Investigations of the Cu substitution by other valence cations (Fe, Co, Cr [3–5]) were performed to reveal the role of the Cu–O sheets and Cu–O pyramids on the high-Tc superconductivity. In the presented work we report the Cu/Mn substitution effect on the (BiPb)–(SrBa)–Ca–Cu–O superconductor.
2. Experimental Samples were prepared by the solid-state reaction method with partial substitution of Bi by Pb
0921-4526/02/$ - see front matter r 2002 Elsevier Science B.V. All rights reserved. PII: S 0 9 2 1 - 4 5 2 6 ( 0 2 ) 0 0 8 6 5 - 7
A. Sidorenko et al. / Physica B 321 (2002) 298–300
299
Bi1.6Pb0.4(Sr1.8Ba0.2 )Ca2(Cu
1-X
MnX)3O y
1.0
R T /R290K
0.8
X=0 X=0.02 X=0.05 X=0.13 X=0.15 X=0.17 X=0.19 X=0.21 X=0.23 X=0.25
0.6 0.4 0.2
0.0 100
150
200
250
300
Temperature, K
Fig. 2. Temperature dependence of the electrical resistance for samples with 0oxo0:3: Fig. 1. Phase contents (vol%) and critical current density Jc for the investigated samples (Bi0.8Pb0.2)2(Sr0.9Ba0.1)2Ca2(Cu1xMnx)3O10+y versus Mn concentration x:
and Sr by Ba to stabilize the high-Tc 2223-phase. XRD analysis confirmed the existence of the 2223 single phase for samples with x ¼ 0: In samples with 0:02oxo0:3 low-Tc 2212-, and 2201phases were detected (see Fig. 1). Neutron diffraction measurements, performed using a timeof-flight diffractometer, show no changes of the diffraction spectrum of (Bi0.8Pb0.2)2(Sr0.9Ba0.1)2Ca2(Cu1xMnx)3O10+y samples related to a Mn magnetic ordering for the whole temperature range 20 KoTo300 K investigated. The DC magnetization measurements for 2 KoTo400 K were carried out in a SQUID magnetometer at a low measuring field, B ¼ 5 mT.
3. Results and discussion An EDX three-element scan (Ca, Mn, and Cu) shows a homogeneous distribution of these elements within the sample. No enhanced concentration of Mn at the grain boundaries was found. A scan of a single 2223 grain verifies the penetration of Mn into the crystal lattice. In Fig. 2 the temperature dependence of the electrical resistance, RðTÞ; is shown, normalized to the value R290 at room temperature. Results of
Fig. 3. Temperature dependence of the DC susceptibility for samples with 0oxo0:2: Tconset is marked by an arrow.
measurements of the DC diamagnetic response are plotted in Fig. 3. Nearly no change of Tconset ¼ 108 K was observed for a wide Mn concentration range, 0oxo0:2: The substitution of Cu by Mn in the Cu–O pyramids and not in the Cu–O sheets of the 2223 lattice may be the reason. The broadening of the superconducting transitions and lowering of the critical current density with increasing Mn concentration seems to indicate an increase of the low-Tc 2212- and 2201-phase content (see Fig. 1), weakening the intergrain coupling.
300
A. Sidorenko et al. / Physica B 321 (2002) 298–300
Acknowledgements This work was supported by the INTAS Grant No. 99-00585.
References [1] Hiroshi Maeda, Kazumasa Togana (Eds.), Bithmuth-based high-temperature superconductors, Marcel Dekker Inc., New York, 1996.
[2] M. Zhiguiang, F. Chenaggao, S. Lei, Y. Zhen, Y. Li, W. Yu, Phys. Rev. B 4 (1993) 14427. [3] G. Ilonca, A.V. Pop, C. Corega, I.I. Geru, V.G. Canter, L.A. Konopko, Y. Min, R. Deltour, Physica C 235–240 (1994) 1391. [4] K. Yanagisawa, Y. Matsui, K. Shoda, E. TakayamaMuromachi, S. Horiuchi, Physica C 196 (1992) 34. [5] D. Ciurcha, A.V. Pop, O. Cozar, Gh. Ilonca, V.I. Geru, V. Pop, L.A. Konopko, Supercond. Sci. Technol. 9 (1996) 88.
The effect of Cu/Mn substitution in 2223 Bi-based HTSC A. Sidorenkoa,b,*, E.-W. Scheidta, F. Haidera, M. Klemma, S. Horna, L. Konopkob, R. Tidecksa a
Institut fur . Physik, Universitat . Augsburg, D-86159 Augsburg, Germany b Institute of Applied Physics, MD-2028 Kishinev, Moldova
Abstract The effect of partial Cu by Mn substitution in the 2223 high-Tc superconductor (Bi0.8Pb0.2)2(Sr0.9Ba0.1)2Ca2(Cu1xMnx)3O10+y with Mn concentration in the range 0oxo0:3 was studied by resistivity, DC susceptibility, XRD, EDX, and neutron diffraction measurements. The EDX analysis confirmed the Mn presence inside the grains in Mndoped samples. Neutron diffraction measurements show no evidence for magnetic ordering of Mn for 20 KoTo300 K: The critical temperature, Tconset ; of the samples, determined from the temperature dependence of the electrical resistivity, RðTÞ; and from the diamagnetic response, MðTÞ; show no changes of Tconset ¼ 108 K for a wide Mn concentration range, 0oxo0:2: A substitution of Cu by Mn in the Cu–O pyramids and not in the Cu–O sheets of the 2223 lattice may be the reason of the Mn concentration independence of Tconset : r 2002 Elsevier Science B.V. All rights reserved. Keywords: Superconductivity; High-Tc ; Bi-2223
1. Introduction Bi-based cuprate superconductors represented by the series Bi2Sr2Can1CunO2n+4 with n ¼ 123 have some important properties for basic science and applications: (1) a highly waved modulated crystal structure; (2) highly anisotropic twodimensional superconductivity; (3) the possibility of obtaining high grain alignment even in polycrystalline samples. In order to obtain information about the mechanism of the formation of modulated structures, as well as on the relation between modulation and superconductivity, the effects of *Corresponding author. Institut fur . Physik, Universit.at Augsburg, D-86159 Augsburg, Germany. Fax: +49-8215983225. E-mail address: [email protected] (A. Sidorenko).
partial substitution of Bi- or Cu-sites with other cations have been intensively studied [1]. It was found that partial Sr substitution by Ba leads to a reduction of the modulation period and to an increase of Tconset ; while partial Bi substitution by Pb promotes and stabilizes the high-Tc 2223-phase [2]. Investigations of the Cu substitution by other valence cations (Fe, Co, Cr [3–5]) were performed to reveal the role of the Cu–O sheets and Cu–O pyramids on the high-Tc superconductivity. In the presented work we report the Cu/Mn substitution effect on the (BiPb)–(SrBa)–Ca–Cu–O superconductor.
2. Experimental Samples were prepared by the solid-state reaction method with partial substitution of Bi by Pb
0921-4526/02/$ - see front matter r 2002 Elsevier Science B.V. All rights reserved. PII: S 0 9 2 1 - 4 5 2 6 ( 0 2 ) 0 0 8 6 5 - 7
A. Sidorenko et al. / Physica B 321 (2002) 298–300
299
Bi1.6Pb0.4(Sr1.8Ba0.2 )Ca2(Cu
1-X
MnX)3O y
1.0
R T /R290K
0.8
X=0 X=0.02 X=0.05 X=0.13 X=0.15 X=0.17 X=0.19 X=0.21 X=0.23 X=0.25
0.6 0.4 0.2
0.0 100
150
200
250
300
Temperature, K
Fig. 2. Temperature dependence of the electrical resistance for samples with 0oxo0:3: Fig. 1. Phase contents (vol%) and critical current density Jc for the investigated samples (Bi0.8Pb0.2)2(Sr0.9Ba0.1)2Ca2(Cu1xMnx)3O10+y versus Mn concentration x:
and Sr by Ba to stabilize the high-Tc 2223-phase. XRD analysis confirmed the existence of the 2223 single phase for samples with x ¼ 0: In samples with 0:02oxo0:3 low-Tc 2212-, and 2201phases were detected (see Fig. 1). Neutron diffraction measurements, performed using a timeof-flight diffractometer, show no changes of the diffraction spectrum of (Bi0.8Pb0.2)2(Sr0.9Ba0.1)2Ca2(Cu1xMnx)3O10+y samples related to a Mn magnetic ordering for the whole temperature range 20 KoTo300 K investigated. The DC magnetization measurements for 2 KoTo400 K were carried out in a SQUID magnetometer at a low measuring field, B ¼ 5 mT.
3. Results and discussion An EDX three-element scan (Ca, Mn, and Cu) shows a homogeneous distribution of these elements within the sample. No enhanced concentration of Mn at the grain boundaries was found. A scan of a single 2223 grain verifies the penetration of Mn into the crystal lattice. In Fig. 2 the temperature dependence of the electrical resistance, RðTÞ; is shown, normalized to the value R290 at room temperature. Results of
Fig. 3. Temperature dependence of the DC susceptibility for samples with 0oxo0:2: Tconset is marked by an arrow.
measurements of the DC diamagnetic response are plotted in Fig. 3. Nearly no change of Tconset ¼ 108 K was observed for a wide Mn concentration range, 0oxo0:2: The substitution of Cu by Mn in the Cu–O pyramids and not in the Cu–O sheets of the 2223 lattice may be the reason. The broadening of the superconducting transitions and lowering of the critical current density with increasing Mn concentration seems to indicate an increase of the low-Tc 2212- and 2201-phase content (see Fig. 1), weakening the intergrain coupling.
300
A. Sidorenko et al. / Physica B 321 (2002) 298–300
Acknowledgements This work was supported by the INTAS Grant No. 99-00585.
References [1] Hiroshi Maeda, Kazumasa Togana (Eds.), Bithmuth-based high-temperature superconductors, Marcel Dekker Inc., New York, 1996.
[2] M. Zhiguiang, F. Chenaggao, S. Lei, Y. Zhen, Y. Li, W. Yu, Phys. Rev. B 4 (1993) 14427. [3] G. Ilonca, A.V. Pop, C. Corega, I.I. Geru, V.G. Canter, L.A. Konopko, Y. Min, R. Deltour, Physica C 235–240 (1994) 1391. [4] K. Yanagisawa, Y. Matsui, K. Shoda, E. TakayamaMuromachi, S. Horiuchi, Physica C 196 (1992) 34. [5] D. Ciurcha, A.V. Pop, O. Cozar, Gh. Ilonca, V.I. Geru, V. Pop, L.A. Konopko, Supercond. Sci. Technol. 9 (1996) 88.