Regensburg 2016 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

TT: Fachverband Tiefe Temperaturen

TT 19: Superconductivity: Poster Session

TT 19.24: Poster

Montag, 7. März 2016, 15:00–18:00, Poster D

Crystal growth of YFe₂Ge₂ and the dependence of its superconducting properties on sample preparation — •Jiasheng Chen¹, Konstantin Semeniuk¹, Zhuo Feng², Pascal Reiss¹, Philip Brown¹, Giulio Lampronti³, and Malte Grosche¹ — ¹Cavendish Lab., Cambridge, UK — ²London Centre of Nanotechnology, UCL, London, UK — ³Dept. of Earth Sciences, Cambridge, UK

The d-electron system YFe₂Ge₂ exhibits an unusually high Sommerfeld ratio of specific heat capacity of C/T ∼ 100 mJ/(molK²), signaling strong electronic correlations. Evidence of superconductivity has been reported in polycrystals and in flux-grown single crystals [1] with residual resistance ratios (RRR) of the order of 50, but these samples show no thermodynamic signatures of a bulk superconducting transition. We find that by combining (i) a prereaction of YFe₂, (ii) careful control of nominal composition, and (iii) subsequent annealing procedures, the polycrystalline YFe₂Ge₂ samples grown using a radio-frequency (RF) induction furnace can reach RRR values ∼ 200 with resistive superconducting transitions temperatures of around 1.85 K. This new generation of sample displays clear heat capacity anomalies as well as nearly 100% diamagnetic screening, confirming the bulk nature of its superconductivity.[2] We present details of the sample preparation and characterization and discuss the correlation between nominal composition and superconductivity.
Y. Zou et al., Physica Status Solidi (RRL) 8, 928 (2014)
J. Chen et al., arXiv:1507.01436v2.