Seminarium Międzynarodowego Laboratorium Silnych Pól Magnetycznych i Niskich Temperatur PAN
ul. Gajowicka 95, sala seminaryjna (nowy budynek, II piętro)
The vortex-glass behavior in Ba(Fe,Ni)2As2 single crystals and critical currents in FeSe
Vladimir A. Vlasenko
Lebedev Physical Institute of the Russian Academy of Sciences (LPI RAS), Moscow
We report that for Ni-doped Ba(Fe,Ni)2As2 samples and for magnetic field H//c-axis, the curves of normalized pinning force fp=FP/Fpmax vs h=H/Hirr, measured at different temperatures fall in a single curve with peak position hmax≈0.33 for BaFe1.86Ni0.14As2 crystal and hmax≈ 0.4 for BaFe1.9Ni0.1As2 sample, indicating single dominating normal point pinning mechanism. In the H//ab-planes configuration c-axis fp(h) curves show no scaling. Temperature dependence of the resistance as well as I(V)-characteristics may be described within a vortex-glass model. Also we report successful fabrication of FeSe superconductive wire made by ex-situ Fe-diffusion PIT (Powder in tube) method. The original wire shows transport Jc as high as 75 A/cm2 at helium temperature (4.0K), while heat treated sample shows 60% enhancement of Jc, reaching the value of 127 A/cm2.
