Ferromagnetic tendencies at the surface of AF/CO bulk manganites

ORAL

Abstract

Previous investigations have shown that the surface of a ferromagnetic (FM) manganite has antiferromagnetic (AFM) tendencies. However, the development of ferromagnetism has been observed experimentally in some AFM charge-ordered (CO) manganites by reducing the grain size down to the nanoscale. Similar phenomenon was also found in other nanosized CO oxides, such as La$_{1/3}$Sr$_{2/3}$FeO$_{3}$. To clarify these puzzling observations, using Monte Carlo techniques we studied the FM Kondo model, using open boundary conditions to simulate a surface. For some values of the couplings, the previously known tendency to an AFM outer shell was found for the case of a bulk FM state. But for other couplings, the opposite effect was observed: the existence of a FM layer at the surface of a AFM/CO material. Details will be provided in this presentation.

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Authors

  • Shuai Dong

    Department of Physics and Astronomy, University of Tennessee and Materials Science and Technology Division, Oak Ridge National Laboratory

  • Rong Yu

    Department of Physics and Astronomy, University of Tennessee and Materials Science and Technology Division, Oak Ridge National Laboratory, Department of Physics, University of Tennessee

  • Seiji Yunoki

    Department of Physics and Astronomy, University of Tennessee and Materials Science and Technology Division, Oak Ridge National Laboratory

  • Elbio Dagotto

    Oak Ridge Natl. Lab. and Univ. Tennessee, TN, USA, Department of Physics and Astronomy, University of Tennessee and Materials Science and Technology Division, Oak Ridge National Laboratory, Department of Physics, University of Tennessee and Condensed Matter Sciences Division, ORNL