Flux Dynamics of iron-based Superconductors

1
Flux Dynamics of iron-based Superconductors
Bin Lv , X S Wu, H M Shao
National Lab of Solid State Microstructures,
Nanjing University, Nanijng210093, China
Introduction
Microcosmic defects
Vortex- glass
Vortex lines
Hexangular Crystalline order
H
Defects center of material
In the presence of pinning, the long rang
crystalline order of the Abrikosov lattice is
destroyed. By taking into account both pinning
and collective effects of the vortex lines, at
low T in a bulk system, the vortex lines should
freeze into vortex-glass phase. 1
Theory and model
Vortex-glass phase
Vortex-liquid phase
Normal phase
Previous function 1
TcgtTgtTg
1D
T
By consider the effect of magnetic field, we
introduce another dimensionality-B.
Tc
Tg
New function
TcgtTgtTg
2D
We have a more accurate description of
vortex-glass.
U0(T,B)gtU vortex-glass U0(T,B)ltU
vortex-liquid
Use the experiential expression from experiment
2
We did different expansion in different T
region, finally we get two theory curve, which
can fit the original data quite well.
This is the first time that one could get the
R-T curve at high T region from the glass theory.
Moreover, we found that in Ba0.6K0.4Fe2As2,
the exponent v(z-1) decrease with the magnetic
field increase, not an irregular variety as
observed in cuprate superconductors.
Acknowledgement This work has been supported
by NNSFC (10774065, 10523001, 10974081) and
NKPBRC (2006CB921802, 2010CB923404)
Reference 1 R.H.Koch et al. PRL.63(1989)
1511 2 A. Rydh et al. PRL.83(1999) 1850