Evidence of a Bose-glass transition in superconducting YBa2Cu3O7 single crystals with columnar defects

Abstract

Experimental evidence of a Bose-glass transition in the vortex state of ${\mathrm{YBa}}_2$ ${\mathrm{Cu}}_3$ ${\mathrm{O}}_7$ single crystals with columnar defects along the c axis is manifested by the universal critical exponents ${\nu }_{\mathrm{\perp }}$, ${\nu }_{\mathrm{\parallel }}$ (≡ζ${\nu }_{\mathrm{\perp }}$), and z’ derived from the (d’+1)-dimension critical scaling of the frequency-dependent ac resistivity from ${10}^2$ to 2.5×${10}^6$ Hz. The Bose-glass transition temperature (${\mathit{T}}_{\mathrm{BG}}$) is found to decrease with the increasing angle (θ) between the applied magnetic field and the c axis. The finding that ζ=${\nu }_{\mathrm{\parallel }}$/${\nu }_{\mathrm{\perp }}$=1.1±0.1<d’=2 suggests an incompressible Bose glass at temperatures below ${\mathit{T}}_{\mathrm{BG}}$.