Hall effect studies of the mixed and normal states of Y1−xPrxBa2Cu3O7−δ(0 ≤ x ≤ 1) and YBa2Cu3Oy (6.35 ≤ y ≤ 7) single crystals

Physica

C 235-240

PHYSICA

(1994)3119-3120

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North-Holland

Hall effect studies of the mixed and normal states of Y l - x P r x B a 2 C u 3 0 7 - 8 (0 ___x _< 1 ) and Y B a 2 C u 3 O y (6.35 < y _ 7) single crystals C. C. Almasan a, S. H. Han a, K. Yoshiara a,1 , M. Buchgeister a, D. A. Gajewski a, J. Herrmann a,

A. P. Paulikasb, Chun Gub, B. W. Vealb, and M. B. Maple a aDepartment of Physics and Institute for Pure and Applied Physical Sciences, University of California, San Diego, La Jolla, CA 92093, USA bArgonne National Laboratory, Argonne, IL 60439, USA

Hall effect measurements on single crystal specimens of Yl-xPrxBa2Cu307-8 (0 _6.73, Vxy is positive for T > Tc and displays a "negative Hall anomaly" a few degrees below Tc which shifts to higher fields at lower temperatures. A similar behavior was reported by Jia et al. [3] and Xiong and Xiao [4]. The negative Hall region occurs where Vxx increases rapidly with increasing field [1,2]. For x > 0.24 or y < 6.73, only a positive Hall signal is observed. Figure 1 contains a plot of the magnitude of the minimum Hall signal A, obtained from 0921-4534/94/$07.00

SSDI

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0921-4534(94)02125-2

1994

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Elsevier

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Fig. 1. Magnitude of the minimum value t~ of Vxy(H) for single crystals of YBa2Cu3Oy and Yl-xPrxBa2Cu307-5 taken at different temperatures vs reduced temperature T/Tc. The data exhibit a maximum Areax which is plotted in the inset vs Tc.

reserved.

3120

C.C. Almasan et al./Plo,sica C 235 240 (1994) 3119 3120

Vxy vs H curves, vs the reduced temperature T/T c, for both systems. The result for x = 0 is similar to the one reported by Luo et al. for epitaxial YBa2Cu307 films [5]. The interesting features of all these curves is that, for both systems, A is nonzero over the same reduced temperature range (0.88
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To(K) Fig. 2. Slope A and intercept B vs T c for Yl-xPrxBa2Cu307-a and YBa2Cu3Oy single crystals. The value of H was 6T. This research was supported by the U. S. Department of Energy under Grant No. DEFG03-86ER-45230. MB acknowledges partial support from the Alexander-von Humboldt Foundation; JH acknowledges support from the German Academic Exchange Service. 1permanent address: Material and Electronic Devices Laboratory, Mitsubishi Electric Corp., Sagamihara, Kanagawa, Japan

REFERENCES

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M. B. Maple et al., Journal of Superconductivity 7, 97 (1994). C.C. Almasan et al., Physica B (in press). Y.X. Jia, J. Z. Liu, M. D. Lan, and R. N. Shelton, Phys. Rev. B 47, 6043 (1993). P. Xiong, G. Xiao, and X. D. Wu, Phys. Rev. B 47, 5516 (1993). J. Luo et al., Phys. Rev. Lett. 68, 690 (1992). R.C. Budhani, S. H. Liou, and Z. X. Cai, Phys. Rev. Lett. 71, 621 (1993). P. W. Anderson, Phys. Rev. Lett. 67, 2992 (1991). W. Jiang, J. L. Peng, S. J. Hagen, and R. L. Greene, Phys. Rev. B 46, 8694 (1992).