Magnetoresistivity near the superconducting transition of high temperature copper oxide superconductors with non-uniformly distributed Tc inhomogeneities

• Published in: Cryogenics (Guildford) Vol. 37; no. 10; pp. 563 - 566
• Main Authors: Mosqueira, J., Siebold, Th, Pomar, A., Díaz, A., Veira, J.A., Maza, J., Vidal, F.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford Elsevier Ltd 1997; Elsevier
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; electrical resistivity; Exact sciences and technology; HTSC; inhomogeneities; Physics; Properties of type I and type II superconductors; Superconductivity; Transport properties (electric and thermal conductivity, thermoelectric effects, etc.); inhomogeneities; HTSC; electrical resistivity; Negative magnetoresistance; Network structure; Inorganic compounds; Magnetic field effects; Bismuth oxides; High temperature superconductors; Current voltage characteristics; Nonstoichiometry; Calcium oxides; Strontium oxides; Thallium oxides; Multi-element compounds; Transition metal compounds; Anisotropy; Barium oxides; Anomaly; Models; Magnetoresistance; Copper oxides; Superconducting transition; Yttrium oxides
• ISSN: 0011-2275; 1879-2235
• DOI: 10.1016/S0011-2275(97)00069-6

We have measured the in-plane magnetoresistivity,
p(T,H), of YBa
2Cu
3O
7 − δ, Bi
2Sr
2Ca-Cu
2O
8 and TI
2Ba
2Ca
2Cu
3O
10 crystals with small stoichiometric inhomogeneities at long length scales and uniformly and non-uniformly distributed in the crystals. These stoichiometric inhomogeneities (mainly of the oxygen content) lead to
T
c inhomogeneities, which deform the
p(T,H) curves mainly near
T
c. In the case of non-uniformly distributed inhomogeneities, sharp
p(T,H) peaks may also appear, very sensitive to the applied magnetic field. This leads to a very anisotropic and negative magnetoresistivity. We will show that these different effects may be explained at a quantitative level in terms of temperature dependent electrical current redistributions.