Cu site substitution effect on the Hall coefficient of La2−xSrxCuO4

The Cu site substitution effects on the Hall coefficient R_H and the electrical resistivity have been studied for La_2?xSr_xCuO₄. In a small x region, R_H decreases largely with Zn doping and increases with Ni doping. In the Ni doped samples, shows the characteristic temperature dependence similar to those of the unsubstituted samples where the decrease of the slope of vs. T curve is observed for x<0.1 above 600K but in the Zn doped samples, the change of the slope of becomes smaller,i.e. the temperature dependence of below 600K becomes smaller. These results indicate that the origin of the change of the slope of around 600K for x<0.1 is magnetic and the spin correlation or the electronic state is rather different below and above 600K. The unusual Zn doping dependences of R_H and are naturally explained by considering that the electronic state at high temperatures above 600K which has a small Hall coefficient expected for the large Fermi surface comes down to lower temperatures by the Zn doping.