Thermoelectric Effect in Normal-State YBa 2 Cu 3 O 7-δ Films

Signal pulses of several 100 volts and currents of several amperes have been obtained at lateral surface contacts on normal-state YBa 2 Cu 3 O 7-δ films in response to pulsed laser irradiation. The signals are shown to be of thermoelectric origin. Thermoelectric fields transverse to the laser-induced temperature gradient are due to the anisotropy of the thermopower in YBa 2 Cu 3 O 7-δ giving rise to non-zero off-diagonal elements S ij ∝ α of the Seebeck tensor for films prepared with a tilt angle α between the film c -axis and the film surface normal. Large-tilt-angle films (up to α = 20°) could be grown on specially cut substrates and may be useful as almost wavelength-independent room temperature radiation detectors.