The effect of hydrogenation upon superconductivity in layered [formula omitted

Abstract

We report on hydrogenation of the layered boronitride superconductor La 3 Ni 2 B 2 N 3 - δ . Bulk specimen have been hydrogenated at 27 bar and temperatures ranging from 70 to 120 ∘ C yielding a series La 3 Ni 2 B 2 N 3 - δ H x with x = 0.6 and 1.0 which exhibits a rather small volume expansion, Δ V / V ≃ 0.05 % / f . u . hydrogen. Specific heat and magnetic susceptibility studies of samples with x = 0 , 0.6, and 1.0 reveal a clear bulk effect of hydrogenation upon the superconducting properties, e.g. an increase of T c by about 0.5 K, as well as an increase of H c ( T ) and H c 2 ( T ) .