DQMP Forum - Domitille Remini Baux - Célia Lucas Esparseil

09.12.2025 13:00 – 14:00

Investigating strain effects on the far-infrared response of SrTiO3 membranes
Domitille Remini Baux (group of Dr. Kuzmenko)

Phonon polaritons (PhPs), hybrid light–lattice excitations, provide strong field confinement within Reststrahlen Bands (RBs), where the real part of the permittivity is negative. SrTiO3 membranes were recently shown to host far-infrared PhPs [1, 2]. Here, we explore mechanical strain, applied using a piezoelectric strain device, to tune the vibrational and polaritonic response of SrTiO3 membranes transferred onto flexible polyimide. The strain application approach [3] will be described, along with first far-field infrared measurements. Ultimately, this work aims to explore how strain can control PhP propagation, providing a versatile platform for infrared photonics.
[1] K. Koons et al., Adv. Funct. Mater. 35, 2501041 (2025)
[2] R. Xu et al., Nat. Commun. 15, 4743 (2024)
[3] J. Li et al., Nat. Commun. 16, 4445 (2025)


Experimental Study on Delamination Induced by Electromagnetic Forces in REBCO Tapes
Célia Lucas Esparseil (group of prof. Senatore)

Given the exceptional superconducting properties of REBCO coated conductors (CCs), their use in highfield magnet applications has increased significantly in recent years. However, their multilayer structure represents a major intrinsic weakness, and numerous magnet failures from conductor delamination have been reported [1, 2]. This work presents an experiment to evaluate the delamination strength of commercial REBCO CCs. Transverse tensile stress was induced by electromagnetic forces, allowing assessment of damage under near-service conditions. Tests were performed in magnetic fields up to 19 T and currents up to 2 kA, producing transverse stresses up to ∼10 MPa. A custom-designed holder, optimized through numerical analysis, was developed to minimize hoop-stress contribution. Post-mortem analysis included inductive mapping of the local critical current density and SEM/EDX characterization, revealing the distribution, mechanisms, and chemical nature of the damage. Additional forensic examination identified localized compositional changes consistent with thermal instabilities concurrent with delamination.
[1] S. Hahn et al., Nature 570, 496 (2019)
[2] L. Shao et al., IEEE TAS 33 (2023)

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Bâtiment: Ecole de Physique

Auditoire Stückelberg

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