Transverse resistance in HoBa2Cu3O7-delta single crystals

摘要

The transverse electrical resistance of HoBa2Cu3O7-delta single crystals is investigated in the temperature range T-c-300 K for optimally-doped (T-c approximate to 91 K) and oxygen-poor (T-c approximate to 51 K) samples. With decreasing temperature, the resistivity of the optimallydoped samples has been found to transit from the regime of scattering on phonons and defects to the regime of "semiconductor" character and, near T-c, of the fluctuation conductivity. The oxygen-poor samples have been revealed to exhibit only a variable range hopping conductivity of "semiconductor" character, which near T-c transits into the fluctuation conductivity. A significant anisotropy of the residual resistivity and characteristics of the fluctuation conductivity is observed for samples of both types.