European physical journal b vol:42 issue:3 pages:367-371
Magnetoresistance (MR) of Bi-2212 single crystals with T-c approximate to 87 - 92 K is studied in pulsed magnetic fields tip to 50 T along the c-axis in a wide temperature range. The negative out-of-plane and the positive in-plane MRs are measured in the normal state. Both MRs have similar magnitudes, exceeding any orbital contribution by two orders in magnitude. These are explained as a result of the magnetic pair-breaking of preformed pairs. Resistive upper critical fields H-c2(T) determined from the in- and out-of-plane MRs are about the same. They show non-BCS temperature dependences compatible with the Bose-Einstein condensation field of preformed charged bosons.