Role of self-irradiation defects on the ageing of 239PuCoGa5

6 pages, 18 referencesInternational audienceLow-temperature accumulation and annealing experiments, in conjunction with electrical resistivity and critical current density measurements, were used to study the ageing of the actinide superconductor PuCoGa5. These measurements reveal that 2-nm sized non-superconducting point-like regions are the main damage formed during room temperature ageing; smaller point-like defect were irrelevant to transport properties. Defect sizes and densities deduced from experiment agree with Transmission Electron Micoscopy observations

Systematics in PuTGa5 Compounds (invited talk)

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Systematic Investigation of the Superconducting Behaviour in Aged PuCoGa5 (invited talk)

In this work, we have undertaken to follow the evolution of the PuCoGa5 superconducting behavior as a function of the damages created by self-radiation effects induced from the Pu-decay. It is shown that the critical temperature is particularly sensitive with ageing. Ageing effects on fundamental parameters such as the lattice parameters of the PuCoGa5 and the electrical resistivity provide some new hints of the unconventional character of the superconductivity in this class of materials.JRC.E.6-Actinides researc

Tuning the Superconducting Behaviour of the PuTGa5 Compounds

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Pressure Effect on the Superconductivity of AnTGa5 Systems and Americium Metal (An=Np, Pu, Am - T=Co, Rh, Ir)

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Influence of Self-irradiation Damages on the Superconducting Behaviour of Plutonium -based Compounds

External irradiation of materials creates defects and induces lattice disorders. Interestingly, defects are sometimes helpful for technological purposes. Hence, controlled defect creation has drawn prime attention, in particular on superconductors (especially A15 phases and high temperature superconductors), to make them economically viable by improving their critical current density (irradiation-induced defects act as pinning centres for vortices, which are quantized magnetic fluxes entering the material)1. In this context, the discovery of PuCoGa5 2 and PuRhGa5 3 superconductors is very interesting: first, they represent two new cases of non-conventional superconductors4,5 and second, they provide unique cases to study the impact of self-radiation damage (due to the α-decay of the Pu atoms) on the superconducting critical parameters. In this work, we report about ageing effects in 239PuCo1-xRhxGa5 solid solutions to improve our understanding of the interactions between defects and vortices, without performing any extra irradiation experiment. The evolution with time of the critical parameters (Tc, Hc2, Jc) has been followed by SQUID magnetometry and electrical resistivity measurements.JRC.E.6-Actinides researc

Specific Heat in Pu1-xAmxCoGa5 System

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Influence of Self-Irradiation Damages on the Superconducting Behaviour of Pu-Based Compounds

Ageing effects on the critical parameters (Tc, Hc2) of the superconductors PuCoGa5 and PuRhGa5 are presented. A linear diminution of the critical temperature versus sample ageing is observed. The diminution rate of Tc is larger for PuRhGa5 (DTc/Dt 0.39 K/month) than for PuCoGa5 (DTc/Dt 0.24 K/month). The damages created by selfirradiation (from 239Pu decay) also actas pinning centres, enhancing Hc2(0) with ageing. After 532 days, the PuCoGa5 sample shows an increase of its Hc2(0) up to1350 kOe, whereas in the case of PuRhGa5, the damages produced after only 323 days of ageing destroy the superconductivity. These results suggest that both compounds are surprisingly not equally sensitive to radiation damages.JRC.E.6-Actinides researc

Effects of Self-irradiation Damages on PuTGa5 Superconducting Materials

On one hand, PuCoGa5 and PuRhGa5 are new challenging superconductors [1]. On the other hand, irradiation is an effective method to create defects in materials. A lot of suchexperiments are carried out on High Temperature Superconductors in order to increase their critical current density Jc. The self-radiation damages caused by the α-decay of Pu in these materials is a unique opportunity to study the interactions between defects and vortices, as no extra irradiation is required.JRC.E.6-Actinides researc