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Order-disorder transition in Bi2.1Sr1.9CaCu2O8+d single crystals doped with Fe and Pb

Journal Article


Abstract


  • The magnetic field Hdis(T) where an order-disorder transition of the vortex lattice in high-Tc superconductors occurs, is investigated by measurements of the magnetization M(H) in Bi2.1Sr1.9CaCu2O8+δ (Bi2212) single crystals doped with iron and lead. Comparative studies are made of the temperature dependences of the field Hpeak(T), where the second peak occurs in |M(H)|, and the fields Hmin(T), and Hinfl(T), where a minimum and an inflection point occur at the low-field side of this peak. It is proposed that Hdis(T) lies close to Hinfl. In Bi2.1Sr1.9Ca1.0(Cul-y Fey)2O8+δ single crystals with Fe concentration y=0, 0.005, 0.016, and 0.022, a pronounced peak in the derivative |dM/dH| is observed, whose position Hinfl(T) is independent of temperature T. We relate this peak to the field Hdis(T), which separates a weakly elastically disordered vortex lattice from a plastically disordered vortex solid. In heavily Pb-doped single Bi2212 crystals, Hinfl(T) decreases with increasing T. For the same crystals, a minimum in the normalized relaxation rate S(H) is observed at Hinfl indicating two different flux-creep mechanisms above and below that field and two different solid vortex phases. It is argued that the negative slope of Hdis(T) in heavily-Pb-doped Bi2212 crystals is related to the enhanced c axis conductivity caused by the Pb sitting between the CuO2 layers and causing three-dimensional vortex lines, while in Fe-doped Bi2212 crystals the Fe ions sit on the CuO2 planes and thus do not enhance the coupling between pancake vortices.

Publication Date


  • 2002

Citation


  • Uprety, K. K., Horvat, J., Wang, X. L., Ionescu, M., Liu, H. K., Dou, S. X., & Brandt, E. H. (2002). Order-disorder transition in Bi2.1Sr1.9CaCu2O8+d single crystals doped with Fe and Pb. Physical Review B - Condensed Matter and Materials Physics, 65(22), 2245011-2245017.

Scopus Eid


  • 2-s2.0-0036611822

Web Of Science Accession Number


Start Page


  • 2245011

End Page


  • 2245017

Volume


  • 65

Issue


  • 22

Abstract


  • The magnetic field Hdis(T) where an order-disorder transition of the vortex lattice in high-Tc superconductors occurs, is investigated by measurements of the magnetization M(H) in Bi2.1Sr1.9CaCu2O8+δ (Bi2212) single crystals doped with iron and lead. Comparative studies are made of the temperature dependences of the field Hpeak(T), where the second peak occurs in |M(H)|, and the fields Hmin(T), and Hinfl(T), where a minimum and an inflection point occur at the low-field side of this peak. It is proposed that Hdis(T) lies close to Hinfl. In Bi2.1Sr1.9Ca1.0(Cul-y Fey)2O8+δ single crystals with Fe concentration y=0, 0.005, 0.016, and 0.022, a pronounced peak in the derivative |dM/dH| is observed, whose position Hinfl(T) is independent of temperature T. We relate this peak to the field Hdis(T), which separates a weakly elastically disordered vortex lattice from a plastically disordered vortex solid. In heavily Pb-doped single Bi2212 crystals, Hinfl(T) decreases with increasing T. For the same crystals, a minimum in the normalized relaxation rate S(H) is observed at Hinfl indicating two different flux-creep mechanisms above and below that field and two different solid vortex phases. It is argued that the negative slope of Hdis(T) in heavily-Pb-doped Bi2212 crystals is related to the enhanced c axis conductivity caused by the Pb sitting between the CuO2 layers and causing three-dimensional vortex lines, while in Fe-doped Bi2212 crystals the Fe ions sit on the CuO2 planes and thus do not enhance the coupling between pancake vortices.

Publication Date


  • 2002

Citation


  • Uprety, K. K., Horvat, J., Wang, X. L., Ionescu, M., Liu, H. K., Dou, S. X., & Brandt, E. H. (2002). Order-disorder transition in Bi2.1Sr1.9CaCu2O8+d single crystals doped with Fe and Pb. Physical Review B - Condensed Matter and Materials Physics, 65(22), 2245011-2245017.

Scopus Eid


  • 2-s2.0-0036611822

Web Of Science Accession Number


Start Page


  • 2245011

End Page


  • 2245017

Volume


  • 65

Issue


  • 22