In-plane vortex properties of Bi2Sr2CaCu2O8+x single crystal and ESR anomalies

Inhomogeneity of the intrinsic magnetic field in superconducting YBa2Cu3OXcompounds as revealed by a rare-earth EPR probe

“…A review of possible reasons of the fluctuating magnetic fields in cuprates is given in [31] as well as a new theory is proposed. The calculations based on the relaxation measurements by NMR, EPR, and µSR by using these different theories give very similar to [16] results: ( ) The inhomogeneity caused by Abrikosov´s or Josephson´s FLL leads to the EPR line broadening (see [28,11], for example) 0 min 2 0.120…”

“…In papers [8,11] as well as in our experiments, in contrary, the hysteresis and (or) the line broadening are observed below T irr < T C . The formal approximations of the linewidth by using equation (9) and (11) are presented in Figure 5.…”

“…According to equations ( 11) and ( 12), the influence of the FLL should manifest right below T C as revealed in the most experiments mentioned above. In papers [8,11] as well as in our experiments, in contrary, the hysteresis and (or) the line broadening are observed below T irr < T C . The formal approximations of the linewidth by using equation ( 9) and ( 11) are presented in Figure 5.…”

“…To explain the line broadening by the influence of the flux-line lattice, the authors of [11] were forced to replace T C in equation (11) H⎟⎢C is in the range (0.12-0.16) µm and increases with x reducing (see [32], for example).…”

“…The lineshape, the position and narrow linewidth of DPPH itself are practically temperature independent. In the decoration experiments, however, they depend not only from the temperature but from other detection conditions, such as a frequency and a value of the modulation field, the sweep direction of the applied magnetic field, et al This EPR technique in reference to HTSC, firstly presented by Rakvin et al [4,5], is being actively used and developed (see [6,7,8,9,10,11], for instance).…”