Normal state magnetoresistance in Bi2Sr2CaCu2O8+δ thin films with different oxygen contents

We report preliminary results obtained in a magneto-transport study in the normal state of overdoped (T-c similar to 63 K) and underdoped(T-c similar to 60 K and T-c similar to 30 K) Bi2Sr2CaCu2O8+delta thin films. In all cases the transverse magnetoresistance (H\\c with in-plane current) is positive and proportional to H-2 UP to 20 T for temperatures above approximately 110 K and does not follow Kohler's rule. No proportionality between the magnetoresistance and the square of the Hall angle theta(H) is observed, as would be expected if both quantities were governed by the same relaxation time tau(H) In the high-temperature range the magnetoresistance of the underdoped samples appears to saturate in the vicinity of the temperature T* where the resistivity shows a downturn from T-linear dependence. (C) 1999 Elsevier Science B.V. All rights reserved.