  The effect of zinc doping on the anomalous temperature dependence of the
magnetoresistance and the Hall effect in the normal state was studied in a
series of La{1.85}Sr{0.15}Cu{1-y}Zn{y}O{4} films, with values of y between zero
and 0.12. The orbital magnetoresistance at high temperatures is found to be
proportional to the square of the tangent of the Hall angle, as predicted by
the model of two relaxation rates, for all Zn-doped specimens, including
nonsuperconducting films. The proportionality constant is equal to 13.7+/-0.5
independent of doping. This is very different from the behavior observed in
underdoped La{2-x}Sr{x}CuO{4} films where a decrease of x destroys the
proportionality. In addition, the behavior of the orbital magnetoresistance at
low temperatures is found to be different depending on whether x is changed or
y. We suggest that these differences reflect a different evolution of the
pseudogap in the two cases.
