Studying spin states of single nano-rods of [Fe(Htrz)<sub>2</sub>(trz)](BF<sub>4</sub>) spin-crossover molecules using diamond quantum sensing microscopy

ORAL

Abstract

Spin crossover (SCO) molecules are one of the promising candidates for molecular electronics owing to its thermal, magnetic, and optical switching phenomena. Fe(Htrz)2(trz)](BF4)] SCO polymers show thermal switching between high spin (HS) and low spin (LS) states which are applicable in the thermal sensors or switches [1]. While the bulk magnetic properties of Fe(Htrz)2(trz)](BF4)] molecules are widely studied by magnetometry techniques their properties at the individual level are missing [2]. Here we use nitrogen vacancy (NV) based magnetometry to image individual Fe(II) triazole SCO nano-rods of size varying from 200 to 1000 nm [3]. Scanning electron microscopy (SEM) and Raman spectroscopy are performed to find out the size of the Fe(II) triazole nano-rods and to confirm the spin state of the SCO molecule respectively. The stray magnetic fields produced by individual nano-rods are imaged by NV microscopy as a function of temperature (up to 150 0C) and applied magnetic field (up to 3500 G) and correlated with SEM and Raman. We found that most of LS sates are paramagnetic in contrary to prediction of a diamagnetic behavior [4]. Further, we discuss temperature and size effects on Fe (II) triazole properties. [1] A. A. Blanco, et al., Wiley, Molecules. 27, 1213 (2022). [2] A. A. Blanco et al., Molecules 2022, 27(4), 1213 (2022). [3] I. Fescenko, A. Laraoui, et al., Phy. Rev. App. 11(3), 034029 (2019). [4] S. Lamichhane et al., under preparation.

*This material is based upon work supported by the National Science Foundation/EPSCoR RII Track-1: Emergent Quantum Materials and Technologies (EQUATE), Award OIA-2044049. The research was performed in part in the Nebraska Nanoscale Facility: National Nanotechnology Coordinated Infrastructure and the Nebraska Center for Materials and Nanoscience (and/or NERCF), which are supported by the National Science Foundation under Award ECCS: 2025298, and the Nebraska Research Initiative.

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Presenters

  • Suvechhya Lamichhane

    • Department of Physics and Astronomy and the Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln

Authors

  • Abdelghani Laraoui

    • Department of Mechanical & Materials Engineering, University of Nebraska-Lincoln
    • dowran@unl.edu
    • University of Nebraska - Lincoln

  • Suvechhya Lamichhane

    • Department of Physics and Astronomy and the Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln

  • Kayleigh A McElveen

    • University of Nebraska-Lincoln
    • Department of Chemistry, University of Nebraska-Lincoln

  • Adam D Erickson

    • Department of Mechanical & Materials Engineering, University of Nebraska-Lincoln

  • Shuo Sun

    • Department of Chemistry, University of Nebraska-Lincoln

  • Rupak Timalsina

    • Department of Mechanical & Materials Engineering, University of Nebraska-Lincoln

  • Yinsheng Guo

    • Department of Chemistry, University of Nebraska-Lincoln

  • Rebecca Y Lai

    • University of Nebraska-Lincoln
    • Department of Chemistry, University of Nebraska-Lincoln

  • Sy-Hwang Liou

    • Department of Physics and Astronomy and the Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln