Clathrate hydrate

Physics

Organic chemistry

Hydrogen storage

Analytical Chemistry (journal)

Transition metal

Catalysis

Composite material

Inorganic chemistry

Chemistry

Materials science

Diamond anvil cell

Condensed matter physics

Hydrate

Ammonia borane

Superconducting transition temperature

Alloy

Superconductivity

High pressure

Chromatography

Transition temperature

Biochemistry

Lanthanum

Thermodynamics

Chinese Physics Letters

Recently, the theoretically predicted lanthanum superhydride, LaH 10 ± δ , with a clathrate-like structure was successfully synthesized and found to exhibit a record high superconducting transition temperature T c ≈ 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 LaH 10 ± 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 LaH 10 ± δ with dimensions up to 10 × 20 μ m 2 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 T c ≈ 250 K was confirmed through resistance measurements under various magnetic fields. Our method will facilitate explorations of near-room-temperature superconductors among metal superhydrides.

Superconductivity of Lanthanum Superhydride Investigated Using the Standard Four-Probe Configuration under High Pressures*