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arXiv:2501.04657 · Physical review. B./Physical review. B

Broadband electron paramagnetic resonance spectroscopy of Er 167 : LiYF 4 7 at millikelvin temperatures

Ana Strinić, Patricia Oehrl, Achim Marx, Pavel A. Bushev, Hans Huebl, Rudolf Groß, Nadezhda Kukharchyk

Published Jun 2, 2025• 4 citations
arXivHTMLPDF

Abstract

Rare-earth spin ensembles are a promising platform for microwave quantum memory applications due to their hyperfine transitions, which can exhibit exceptionally long coherence times when using an operation point with zero first-order Zeeman (ZEFOZ) shift. In this work, we use broadband electron paramagnetic resonance (EPR) spectroscopy on Er 167 : LiYF 4 7 single crystals at subkelvin temperatures. By fitting the spin Hamiltonian to the zero-field spectrum, we obtain refined parameters of the magnetic field-independent interactions, such as the hyperfine and quadrupole interaction. We also study the influence of the quadrupole interaction on the hyperfine splitting in the zero and low magnetic field range by analyzing EPR spectra between 0 m T and 50 m T . Our findings highlight the broadband EPR spectroscopy approach as a powerful tool for the precise determination of the spin Hamiltonian parameters and for the characterization of hyperfine transitions in terms of their selection rules and linewidth.

DOI
10.1103/5j7f-wfyl

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Rare-earth spin ensembles are a promising platform for microwave quantum memory applications due to their hyperfine transitions, which can exhibit exceptionally long coherence times when using an operation point with zero first-order Zeeman (ZEFOZ) shift. In this work, we use broadband electron paramagnetic resonance (EPR) spectroscopy on Er 167 : LiYF 4 7 single crystals at subkelvin temperatures. By fitting the spin Hamiltonian to the zero-field spectrum, we obtain refined parameters of the magnetic field-independent interactions, such as the hyperfine and quadrupole interaction. We also study the influence of the quadrupole interaction on the hyperfine splitting in the zero and low magnetic field range by analyzing EPR spectra between 0 m T and 50 m T . Our findings highlight the broadband EPR spectroscopy approach as a powerful tool for the precise determination of the spin Hamiltonian parameters and for the characterization of hyperfine transitions in terms of their selection rules and linewidth.
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