Optimizing the growth of K(Ta_0.6Nb_0.4)O₃ films using pulsed laser deposition and their electro-optic property

Abstract

Deposition condition of (001)-epitaxial K(Ta_0.6Nb_0.4)O₃ (KTN) films on SrRuO₃/SrTiO₃ substrates by pulsed laser deposition was optimized. The optimized KTN film showed a saturated ferroelectric hysteresis loop with large withstand electric field, and the paraelectric to ferroelectric phase transition at room temperature (RT). Electro-optic (EO) property was characterized by modulation ellipsometry at RT, showing the maximum EO coefficient r_c of 42 pm/V, which is larger than the previously reported value for KTN thin films having the same composition. Our findings show the importance of the precise tuning of deposition condition to achieve the large EO response in KTN films, promoting the potential application as a light modulator in EO devices at ambient temperature in the future.