ALTERNATIVE MODELING OF RESISTANCE VERSUS TEMPERATURE CURVES ALONG THE C-DIRECTION OF BI-2212 CRYSTALS, SUGGESTING A POSSIBLE METAL INSULATOR TRANSITION BELOW TC/

Resistivity versus temperature curves of ''semiconducting like'' Bi-22 12 crystals, in the normal state, along the c axis have been modelized by: rho = rho(0) exp {Delta/K(T-Ti)}, introducing a Ti temperature fo r which the resistivity is infinite. The excellent fit which is obtain ed (better than what had been previously obtained without introducing Ti) suggests a possible metal/insulator transition along the c axis at T = Ti. But Ti is below Tc, the superconducting transition temperatur e, so that, below Ti, superconducting crystals would be insulators in the normal state and direct insulator/superconductor transition could be observed.