◆14-09 The Search for Novel Magnetic Phases in Strained SrCoO3 Thin Films

  • 日時:11/10(Mon.)13:30~14:30
  • 場所:PF研究棟2階会議室
  • 講師:Dr. Sara Callori (Bragg Institute, Australian Nuclear Science and Technology)
  • 英題:The Search for Novel Magnetic Phases in Strained SrCoO3 Thin Films
  • 要旨:

    The broad range of many transition metal oxide properties can be tuned by external parameters such as strain, oxygen content, or applied electric or magnetic fields and SrCoO3 is a particularly interesting system for investigation. SrCoO3-x has long been studied due to its propensity to form structurally and magnetically distinct oxygen-vacancy ordered structures. In the fully (or nearly so) oxygenated case, bulk SrCoO3 is cubic and ferromagnetic, a behaviour which has also been observed in moderately strained thin films.
    Recent theoretical work has predicted, however, a transition to an antiferromagnetic state under large compressive or tensile strain. This would also be accompanied by a metal-insulator transition as well as the emergence of a ferroelectric state. We have recently prepared SrCoO3 thin films on several substrates, SrTiO3, DyScO3, and LaAlO3, in order to apply a range of epitaxial strains. Using magnetometry and neutron diffraction techniques, we have demonstrated a transition from a ferromagnetic phase as grown on SrTiO3 (1.8% tensile strain) to an antiferromagnetic phase on DyScO3 (2.7% tensile strain). These results confirm the predicted strong coupling between structure (via strain) and magnetism in SrCoO3 and represent the first step in obtaining new functionalities of this system.