Understanding Defects in Thin Films of the Pyrochlore Frustrated Magnet Tb<sub>2</sub>Ti<sub>2</sub>O<sub>7</sub>

ORAL

Abstract

The highly frustrated magnetism in the rare-earth titanate pyrochlore Tb2Ti2O7 relies on a careful balance of magnetic interactions. Defects in the crystal structure disrupt this balance and may affect magnetic behavior – obscuring the true magnetic ground state. Using reactive-oxide molecular beam epitaxy (MBE), we synthesize thin films of Tb2Ti2O7 with varying composition on YSZ (111) substrates. We use scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS) to observe and characterize point and extended defects in this composition series. We further characterize the films’ magnetic behavior with SQUID magnetometry. While all films remain paramagnetic down to 1.8 K, the frustration index is reduced in off-stoichiometric films.

*This work was supported by the Air Force Office of Scientific Research (MURI Grant No. FA9550-21-1-0429).

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Publication: Anderson, Margaret A., et al. "Defect Engineering in Epitaxial Thin Films of the Pyrochlore Frustrated Magnet Tb2Ti2O7." Chemistry of Materials 36.5 (2024): 2325-2333.

Presenters

  • Margaret A Anderson

    • Harvard University

Authors

  • Margaret A Anderson

    • Harvard University

  • Ismail El Baggari

    • Harvard University
    • The Rowland Institute at Harvard
    • The Rowland Institute at Harvard, Harvard University, Cambridge, MA, USA

  • Charles M Brooks

    • Harvard University
    • Department of Physics, Harvard University, Cambridge, MA, USA

  • Johanna Nordlander

    • University of Zurich

  • Julia A Mundy

    • Harvard University
    • Department of Physics, Harvard University, Cambridge, MA, USA