Superconductivity of Lanthanum Superhydride Investigated Using the Standard Four-Probe Configuration under High Pressures
Abstract
Recently, the theoretically predicted lanthanum superhydride, LaH10 ± δ, with a clathrate-like structure was successfully synthesized and found to exhibit a record high superconducting transition temperature Tc ≈ 250 K at ∼ 170 GPa, opening a new route for room-temperature superconductivity. However, since in situ experiments at megabar pressures are very challenging, few groups have reported the ∼ 250 K superconducting transition in LaH10 ± δ. Here, we establish a simpler sample-loading procedure that allows a relatively large sample size for synthesis and a standard four-probe configuration for resistance measurements. Following this procedure, we successfully synthesized LaH10 ± δ with dimensions up to 10 × 20 μm2 by laser heating a thin La flake and ammonia borane at ∼ 1700 K in a symmetric diamond anvil cell under the pressure of 165 GPa. The superconducting transition at Tc ≈ 250 K was confirmed through resistance measurements under various magnetic fields. Our method will facilitate explorations of near-room-temperature superconductors among metal superhydrides. Supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant Nos. XDB33000000 and XDB25000000), the Beijing Natural Science Foundation (Grant No. Z190008), the National Natural Science Foundation of China (Grant Nos. 11575288, 11921004, 11888101, 11904391, 11834016 and 11874400), the National Key R&D Program of China (Grant Nos. 2016YFA0401503 and 2018YFA0305700), and the Youth Innovation Promotion Association, the Key Research Program of Frontier Sciences and the Interdisciplinary Innovation Team of Chinese Academy of Sciences (Grant Nos. 2016006, JCTD-2019-01, and QYZDBSSW-SLH013).
- Publication:
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Chinese Physics Letters
- Pub Date:
- October 2020
- DOI:
- 10.1088/0256-307X/37/10/107401
- Bibcode:
- 2020ChPhL..37j7401H
- Keywords:
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- 74.70.-b;
- 81.40.Vw;
- 62.50.-p;
- 88.30.rd