Inhomogeneous magnesium hydride synthesized by low temperature ion implantation: weak localization effect

P. Nédellec (1) , L. Dumoulin (1) , J. Burger , H. Bernas (1) , H. Köstler , A. Traverse (1)

1 CSNSM - Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse

Metastable MgHx hydride was prepared by H ion implantation into Mg films at 5 K. The resistivity and magnetoresistance temperature dependence reveal weak localization effects due to atomic disorder. At low hydrogen concentrations, x ≤0.3, the conductivity varies as σ∼log (T), typical of two-dimensional weak localization behaviour. The resistivity is also very sensitive to the sample inhomogeneity, due to H diffusion, which can be modelled by introducing a temperature-dependent geometrical percolating factor G. At higher H concentrations, 0.7 ≤x ≤3, after annealing at 20 K, 50 K and 110 K, the samples also exhibit weak localization but with three-dimensional behaviour i.e. a $\sigma \sim \sqrt{T}$. Our analysis is consistent with the existence of an inhomogeneous system formed by a mixture of two phases with contrasted conduction properties, one of which is a well-behaved metal, while the other displays the localization properties. The results lead us to identify the former phase to a non percolating superconducting phase at low temperature.

Domaines: Articles anciens

P. Nédellec, L. Dumoulin, J. Burger, H. Bernas, H. Köstler, et al.. Inhomogeneous magnesium hydride synthesized by low temperature ion implantation: weak localization effect. Journal de Physique I, 1993, 3 (11), pp.2285-2297. ⟨10.1051/jp1:1993245⟩. ⟨jpa-00246868⟩