Enhanced magnetoresistance properties in La0.7−xSmxCa0.3MnO3 epitaxial films

Abstract

The electrical and magnetic properties of strongly correlated manganese oxides originate from and depend on the coupling of spin, orbital, lattice and other degrees of freedom, and can also be controlled by external stimuli (such as a magnetic field). Here, the films have been prepared using spin-coating method to determine the role of Jahn–Teller (JT) distortion and double exchange (DE) interaction in electronic transport and magnetoresistance (MR) by magnetic field in La${}_{0.7-x}$Sm_xCa${}_{0.3}$MnO₃/SrTiO₃(001). The Sm-induced lattice distortion suppresses the metal-insulator transition temperature and increases the films’ resistivity, which is due to the weakening of the DE interaction between Mn${}^{3+}$–O${}^{2-}$–Mn${}^{4+}$ ions and the enhancement of the single electron bandwidth. Moreover, the MR can be increased to 96.5% and the AMR can be increased to 66.6% under 1 T magnetic field. These findings indicate the importance of JT distortion in multi-field control of hole-doped perovskite manganites.