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Journal de Physique I 3, 11 (1993) 2285-2297
Inhomogeneous magnesium hydride synthesized by low temperature ion implantation: weak localization effect
P. Nédellec1, L. Dumoulin1, J. Burger, H. Bernas1, H. Köstler, A. Traverse1

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.
1 :  CSNSM - Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse
Physique/Articles anciens
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