Journal article

Influence of La and Mn vacancies on the electronic and magnetic properties of LaMnO₃ thin films grown by pulsed laser deposition

  • Marozau, Ivan Department of Physics and Fribourg Center for Nanomaterials - Frimat, University of Fribourg, Fribourg, Switzerland
  • Das, Proloy T. Department of Physics and Fribourg Center for Nanomaterials - Frimat, University of Fribourg, Fribourg, Switzerland - Department of Physics and Meteorology, Indian Institute of Technology, Kharagpur, India
  • Döbeli, Max Laboratory for Ion Beam Physics, ETH Zurich, Switzerland
  • Storey, James G. Callaghan Innovation, Lower Hutt, New Zealand
  • Uribe-Laverde, Miguel A. Department of Physics and Fribourg Center for Nanomaterials - Frimat, University of Fribourg, Fribourg, Switzerland
  • Das, Saikat Department of Physics and Fribourg Center for Nanomaterials - Frimat, University of Fribourg, Fribourg, Switzerland
  • Wang, Chennan Department of Physics and Fribourg Center for Nanomaterials - Frimat, University of Fribourg, Fribourg, Switzerland
  • Rössle, Matthias Department of Physics and Fribourg Center for Nanomaterials - Frimat, University of Fribourg, Fribourg, Switzerland - niversity of Potsdam, Institute of Physics and Astronomy, Germany.
  • Bernhard, Christian Department of Physics and Fribourg Center for Nanomaterials - Frimat, University of Fribourg, Fribourg, Switzerland
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    20.05.2014
Published in:
  • Physical Review B. - 2014, vol. 89, no. 17, p. 174422
English With pulsed laser deposition, we have grown c axis oriented thin films of the nominal composition LaMnO3 (LMO) on LSAT(001) substrates. We find that, depending on the oxygen background pressure during growth, the LMO films contain sizeable amounts of La and/or Mn vacancies that strongly influence their electronic and magnetic properties. Specifically, we show that the Mn/La ratio can be systematically varied from 0.92 at 0.11 mbar to 1.09 at 0.30 mbar of oxygen. The cationic vacancies have markedly different effects that become most pronounced once the samples are fully oxygenated and thus strongly hole doped. All as-grown and thus slightly oxygen-deficient LMO films are ferromagnetic insulators with saturation moments in excess of 2.5 μB per Mn ion, their transport and optical properties can be understood in terms of trapped ferromagnetic polarons. Upon oxygen annealing, the most La-deficient films develop a metallic response with an even larger ferromagnetic saturation moment of 3.8 μB per Mn ion. In contrast, in the oxygenated Mn-deficient films, the ferromagnetic order is strongly suppressed to less than 0.5 μB per Mn ion, and the transport remains insulatorlike. We compare our results with the ones that were previously obtained on bulk samples and present an interpretation in terms of the much stronger disruption of the electronic and magnetic structure by the Mn vacancies as compared to the La vacancies. We also discuss the implications for the growth of LMO thin films with well-defined physical properties that are a prerequisite for the study of interface effects in multilayers.
Faculty
Faculté des sciences et de médecine
Department
Département de Physique
Language
  • English
Classification
Physics
License
License undefined
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Persistent URL
https://folia.unifr.ch/unifr/documents/303758
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