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 (Tc ∼ 63 K) and underdoped (Tc ∼ 60 K and Tc ∼ 30 K) Bi2Sr2CaCu2O8+δ thin films. In all cases the transverse magnetoresistance (H\\c with in-plane current) is positive and proportional to H2 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 θH is observed, as would be expected if both quantities were governed by the same relaxation time τH. 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.