Strain-induced large low-field magnetoresistance in Pr0.67Sr0.33MnO3 ultrathin films

We report magnetoresistance (MR) measurements in very thin Pr0.67Sr0.33MnO3 films (5–15 nm) grown on LaAlO3 (001) substrates. The films are under compressive strain imposed by the lattice mismatch with the substrate. The MR ratio [R(H)−R0]/R0 is ∼92% at H=800 Oe and T=70 K when the magnetic field is applied perpendicular to the film plane and is much smaller when the magnetic field is parallel to the film plane. We suggest that the large low-field MR is due to strain-induced magnetic anisotropy and spin-dependent scattering at domain boundaries.