The transverse laser induced thermoelectric voltages in step flow growth (1-x)Pb(Mg_1/3Nb_2/3)O₃–xPbTiO₃ thin films

This paper reports that the transverse laser induced thermoelectric voltages (LITV) are observed for the first time in the step flow growth (1-x)Pb(Mg_1/3Nb_2/3)O₃–xPbTiO₃ (PMN–PT, x=0.20, 0.33, 0.50) thin films deposited on vicinal-cut strontium titanate single crystal substrates. Because lead magnesium niobate-lead titanate is a solid solution of lead magnesium niobate (PMN) and lead titanate (PT), there are two types of signals. One is wide with a time response of a microsecond, and the other superimposed with the wide signal is narrow with a time response of a nanosecond. The transverse LITV signals depend on the ratio of PMN to PT drastically. Under the irradiation of 28-ns pulsed KrF excimer laser with the 248-nm wavelength，the largest induced voltage is observed in the 0.50Pb(Mg_1/3Nb_2/3)O₃–0.50 PbTiO₃ films. Moreover, the effects of film thickness, substrates, and tilt angles of substrates are also investigated.