Temperature Dependence of the Resistivity Tensor in Superconducting<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Bi</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Sr</mml:mi></mml:mrow><mml:mrow><mml:mn>2.2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Ca</mml:mi></mml:mrow><mml:mrow><mml:mn>0.8</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Cu</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">O</mml:mi></mml:mrow><mml:mrow><mml:mn>8</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>Crystals
Abstract
A strongly anisotropic resistivity tensor was measured from ${T}_{c}=81 \mathrm{to} 600$ K in crystals of the new high-${T}_{c}$ superconductor ${\mathrm{Bi}}_{2}$${\mathrm{Sr}}_{2.2}$${\mathrm{Ca}}_{0.8}$ ${\mathrm{Cu}}_{2}$${\mathrm{O}}_{8}$. The $a\ensuremath{-}b$ plane anisotropy is $\frac{{\ensuremath{\rho}}_{a}}{{\ensuremath{\rho}}_{b}}\ensuremath{\approx}2$, with ${\ensuremath{\rho}}_{a}$ and ${\ensuremath{\rho}}_{b}$ linear in $T$. The perpendicular component ${\ensuremath{\rho}}_{c}\ensuremath{\sim}10$ \ensuremath{\Omega} cm is ${10}^{5}$ greater than ${\ensuremath{\rho}}_{a}$ or ${\ensuremath{\rho}}_{b}$. Evidence for nonmetallic temperature dependence is found for the $\frac{{\ensuremath{\rho}}_{c}}{{\ensuremath{\rho}}_{\mathrm{ab}}}$ resistivity ratio. The data are consistent with the notion of quasiparticle tunneling between planes, but an alternative explanation in terms of weak interplanar coupling by topological defects is also presented.
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