Nanoscale Stray Fields from Micromagnets for Optimal Spin Qubit Architecture
Abstract
On-chip micromagnets generate local magnetic-field asymmetries, enabling electrical control of spin qubits via electric dipole spin resonance and their integration into circuit quantum electrodynamics (QED) architectures. Accurate prediction of spin-qubit performance requires modeling micromagnet stray fields beyond the saturated-magnet approximation, accounting for nonuniform magnetization. Here, we combine thin-film characterization of Co, Co/Ta multilayers, and CoFe films with nanoscale stray-field measurements using NV-center magnetometry in the unsaturated regime to establish a reliable micromagnetic simulation framework. We show that CoFe micromagnets generate antisymmetric fields in double quantum-dot geometries exceeding ±100 mT, owing to their high saturation magnetization and favorable magnetocrystalline anisotropy. For spin qubits coupled to microwave resonators, the predicted spin-photon coupling reaches |gs/gc| ≈ 0.5, where g c denotes the charge-photon coupling strength of the underlying charge qubit, highlighting the potential for high-fidelity operations in circuit QED architectures.
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BibTeX
@article{lopes2026nanoscale,
title = {{Nanoscale Stray Fields from Micromagnets for Optimal Spin Qubit Architecture}},
author = {S Lopes and Q. Schaeverbeke and M. M. Desjardins and D Lacour and M Hehn and F Montaigne},
journal = {Nano Letters},
year = {2026},
month = aug,
doi = {10.1021/acs.nanolett.6c01469},
url = {https://hal.science/hal-05727431v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Nanoscale Stray Fields from Micromagnets for Optimal Spin Qubit Architecture
AU - S Lopes
AU - Q. Schaeverbeke
AU - M. M. Desjardins
AU - D Lacour
AU - M Hehn
AU - F Montaigne
PY - 2026
DA - 2026/08/26
JO - Nano Letters
DO - 10.1021/acs.nanolett.6c01469
UR - https://hal.science/hal-05727431v1
AB - On-chip micromagnets generate local magnetic-field asymmetries, enabling electrical control of spin qubits via electric dipole spin resonance and their integration into circuit quantum electrodynamics (QED) architectures. Accurate prediction of spin-qubit performance requires modeling micromagnet stray fields beyond the saturated-magnet approximation, accounting for nonuniform magnetization. Here, we combine thin-film characterization of Co, Co/Ta multilayers, and CoFe films with nanoscale stray-field measurements using NV-center magnetometry in the unsaturated regime to establish a reliable micromagnetic simulation framework. We show that CoFe micromagnets generate antisymmetric fields in double quantum-dot geometries exceeding ±100 mT, owing to their high saturation magnetization and favorable magnetocrystalline anisotropy. For spin qubits coupled to microwave resonators, the predicted spin-photon coupling reaches |gs/gc| ≈ 0.5, where g c denotes the charge-photon coupling strength of the underlying charge qubit, highlighting the potential for high-fidelity operations in circuit QED architectures.
SN - 1530-6984
SN - 1530-6992
ER -