Microstructure-controlled vortex phases and two-phase superconductivity in (TaNb)0.7(HfZrTi)0.5 revealed by ac magnetostrictive coefficients
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arXiv
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| Auteurs principaux: | , , , , , , , |
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| Format: | Preprint |
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2026
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| _version_ | 1866910004573896704 |
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| author | Yuan, Mengju Xu, Yuze Zhang, Bin Ge, Jun-Yi Wang, Aifeng He, Mingquan Qi, Yanpeng Chai, Yisheng |
| author_facet | Yuan, Mengju Xu, Yuze Zhang, Bin Ge, Jun-Yi Wang, Aifeng He, Mingquan Qi, Yanpeng Chai, Yisheng |
| contents | We investigate flux dynamics in the high-entropy alloy superconductor (TaNb)0.7(HfZrTi)0.5 after annealing (as-cast, 500 °C, 550 °C, and 1000 °C) using a sensitive ac composite magnetoelectric method that measures the complex ac magnetostrictive coefficient (dλ/dH)ac. The resulting vortex phase diagrams show that intermediate annealing (500-550 °C) induces nanoscale clustering, enhances pinning, and produces a pronounced fishtail effect with successive elastic- and plastic-vortex-glass regimes. Flux-jump instabilities appear at 550 °C and persist at 1000 °C, indicating strong pinning and thermomagnetic instability in the low-temperature, low-field regime. Remarkably, the 1000 °C sample exhibits a two-step superconducting response-a double plateau or drop in dλ'/dH and two dissipation peaks in dλ''/dH-demonstrating the coexistence of two superconducting phases with distinct irreversibility and critical-field value. We further show that the resolvability of the two-step (dλ/dH)ac signature is governed by the topological connectivity of the phase-separated microstructure, which controls magnetic shielding between the TaNb-rich network and the (TaNb)0.7(HfZrTi)0.5 parent phase. These results establish a direct microstructure-vortex-state correlation and provide a route to tailoring flux pinning in chemically complex superconductors via thermal processing. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2601_21599 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Microstructure-controlled vortex phases and two-phase superconductivity in (TaNb)0.7(HfZrTi)0.5 revealed by ac magnetostrictive coefficients Yuan, Mengju Xu, Yuze Zhang, Bin Ge, Jun-Yi Wang, Aifeng He, Mingquan Qi, Yanpeng Chai, Yisheng Superconductivity Materials Science We investigate flux dynamics in the high-entropy alloy superconductor (TaNb)0.7(HfZrTi)0.5 after annealing (as-cast, 500 °C, 550 °C, and 1000 °C) using a sensitive ac composite magnetoelectric method that measures the complex ac magnetostrictive coefficient (dλ/dH)ac. The resulting vortex phase diagrams show that intermediate annealing (500-550 °C) induces nanoscale clustering, enhances pinning, and produces a pronounced fishtail effect with successive elastic- and plastic-vortex-glass regimes. Flux-jump instabilities appear at 550 °C and persist at 1000 °C, indicating strong pinning and thermomagnetic instability in the low-temperature, low-field regime. Remarkably, the 1000 °C sample exhibits a two-step superconducting response-a double plateau or drop in dλ'/dH and two dissipation peaks in dλ''/dH-demonstrating the coexistence of two superconducting phases with distinct irreversibility and critical-field value. We further show that the resolvability of the two-step (dλ/dH)ac signature is governed by the topological connectivity of the phase-separated microstructure, which controls magnetic shielding between the TaNb-rich network and the (TaNb)0.7(HfZrTi)0.5 parent phase. These results establish a direct microstructure-vortex-state correlation and provide a route to tailoring flux pinning in chemically complex superconductors via thermal processing. |
| title | Microstructure-controlled vortex phases and two-phase superconductivity in (TaNb)0.7(HfZrTi)0.5 revealed by ac magnetostrictive coefficients |
| topic | Superconductivity Materials Science |
| url | https://arxiv.org/abs/2601.21599 |