Zeeman effect on magnetoresistance in high-temperature superconductors

The Zeeman effect on the magnetoresistance in high-temperature superconductors is investigated above the transition temperature. It is found that this effect is dominant for the positive magnetoresistance in a parallel magnetic field and the phase relaxation time τ_φ can be estimated by the comparison of this term with experimental data of single-crystal films. This value is consistent with the estimation from the orbital effect of the Maki-Thompson term in a perpendicular magnetic field, and the temperature dependence of τ_φ proportional to 1/T is obtained from the experimental data.