Volume 79, Number 5, September 2007
Article Number 57005
Number of page(s) 4
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
Published online 01 August 2007
EPL, 79 (2007) 57005
DOI: 10.1209/0295-5075/79/57005

Magnetic-field$\hbox{--} $induced 3D-to-1D crossover in $\chem{Sr_{0.9}La_{0.1}CuO_{2}}$

T. Schneider0

received 5 June 2007; accepted in final form 11 July 2007; published September 2007
published online 1 August 2007

The effect of the magnetic field on the critical behavior of Sr0.9La0.1CuO2 is explored in terms of reversible magnetization data. As the correlation length transverse to the magnetic field Hi, applied along the i-axis, cannot grow beyond the limiting magnetic length $L_{H_{i}}=(\Phi _{0}/(aH_{i}))^{1/2}$, related to the average distance between vortex lines, one expects a magnetic-field$\hbox{--} $induced finite-size effect. Invoking the scaling theory of critical phenomena we provide clear evidence for this effect. It implies that in type-II superconductors there is a 3D-to-1D crossover line $H_{pi}(T)=(\Phi _{0}/(a\xi _{j0}^{-
}\xi _{k0}^{-}))(1-T/T_{c})^{4/3}$ with $i\ne j\ne k$ and $\xi _{i0, j0, k0}^{- }$ denotes the critical amplitude of the correlation length below Tc. Consequently, below Tc and above Hpi(T) superconductivity is confined to cylinders with diameter LHi(1D). Accordingly, there is no continuous phase transition in the (H, T)-plane along the Hc2-lines as predicted by the mean-field treatment.

74.25.Bt - Thermodynamic properties .
74.25.Ha - Magnetic properties .
74.40.+k - Fluctuations (noise, chaos, nonequilibrium superconductivity, localization, etc.).

© Europhysics Letters Association 2007