Experimental Observation of Short-Range Magnetic Correlations in Amorphous Nb$_2$O$_5$ and Ta$_2$O$_5$ Thin Films

• URL: http://arxiv.org/abs/2505.07957v1
• Date: Mon, 12 May 2025 18:01:05 GMT
• Title: Experimental Observation of Short-Range Magnetic Correlations in Amorphous Nb$_2$O$_5$ and Ta$_2$O$_5$ Thin Films
• Authors: Y. V. Krasnikova, A. A. Murthy, D. Bafia, F. Crisa, A. Clairmont, Z. Sung, J. Lee, A. Cano, M. Shinde, D. M. T. van Zanten, M. Bal, A. Romanenko, A. Grassellino, R. Dhundwal, D. Fuchs, T. Reisinger, I. M. Pop, A. Suter, T. Prokscha, Z. Salman,
• Abstract summary: We investigate the magnetic properties of niobium pentoxide (Nb$$O$_5$) and tantalum pentoxide (Ta$$O$_5$) thin films.<n>In their amorphous phase (sputter-deposited), both oxides exhibit magnetic behavior down to 2.8 K.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: We used muon spin rotation/relaxation/resonance ($\mu$SR) to investigate the magnetic properties of niobium pentoxide (Nb$_2$O$_5$) and tantalum pentoxide (Ta$_2$O$_5$) thin films. In their amorphous phase (sputter-deposited), both oxides exhibit magnetic behavior down to 2.8 K. However, the magnetic response is strongly structure-dependent: thermally-oxidized, poly-crystalline Ta$_2$O$_5$ shows suppressed magnetism, while amorphous Ta$_2$O$_5$ demonstrates local static magnetism. In contrast, amorphous Nb$_2$O$_5$ is significantly more magnetically disordered. These results suggest that magnetic inhomogeneity in the native oxides of Ta and Nb may be a key factor in the performance of superconducting devices, particularly limiting T$_1$ for qubits and resonators.

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