@article{33766,
  author = {S.B Ogale and Y.H Li and M Rajeswari and L.S Riba and Ramamoorthy Ramesh and T Venkatesan and A.J Millis and R Kumar and G.K Mehta and R Bathe and S.I Patil},
  title = {Columnar defect induced phase transformation in epitaxial La0.7Ca0.3MnO3 films},
  abstract = {Epitaxial La0.7Ca0.3MnO3 thin films on the SrTiO3(100) surface have been irradiated with 250 MeV Ag17+ ions at different nominal fluence values in the range of 5 × 1010-4 × 1011 ions/cm2, resulting in columnar defects. At low fluences these defects cause changes in material properties that are small and scale linearly with dosage. Above a threshold fluence value ∼3 × 1011 ions/cm2 dramatic changes are observed, including an order of magnitude increase in the resistivity and 50 K drop in the Curie temperature. Transmission electron microscopy measurements show that the changes are associated with a phase transformation of the undamaged region between the columnar defects. The transformed phase has a diffraction pattern very similar to that seen in charge-ordered La0.5Ca0.5MnO3. We propose that above a critical level of ion damage, strains caused by the presence of the columnar defects induce a charge-ordering phase transition that causes the observed dramatic changes in physical properties. We speculate that a conceptually similar surface-induced charge ordering may be responsible for the "dead layer" observed in very thin strained films, and the dramatic changes in optical properties induced by polishing, and that an impurity-induced charge ordering causes the extreme sensitivity of properties to lattice substitution. © 2000 American Institute of Physics.},
  year = {2000},
  journal = {Journal of Applied Physics},
  volume = {87},
  number = {9 I},
  pages = {4210-4215},
  publisher = {American Institute of Physics Inc.},
  issn = {00218979},
  doi = {10.1063/1.373054},
  note = {cited By 28},
  language = {eng},
}