| Abstract
| - Dielectric thin films of BaTaO2N have been epitaxially grown on SrRuO3/SrTiO3 by pulsed-laser deposition. The BaTaO2N film possesses the unusual coexistence of high dielectric permittivity with negligible temperature dependence. The BaTaO2N lattice undergoes a tetragonal elongation of the unit cell driven by epitaxial strain effects.
- Pulsed-laser deposition was employed to grow epitaxial thin films of the oxynitride perovskite BaTaO2Non a conducting SrRuO3 buffer layer deposited on a 100-cut SrTiO3 single-crystal substrate. Phase purityand epitaxy were optimized at a substrate temperature of 760 °C in a mixed gas atmosphere of 100mTorr N2/O2 (∼20:1). The dielectric permittivity, κ, of the BaTaO2N film was large, exhibiting a slightfrequency dependence ranging from about 200 to 240 over the frequency range 1−100 kHz. Furthermore,over the temperature range 4−300 K the permittivity showed minimal variation as a function oftemperature. The temperature coefficient of the dielectric constant, τκ, is estimated to be in the range of−50 to −100 ppm/K. The coexistence of high dielectric permittivity and weak temperature dependenceis an unusual combination in a single-phase material.
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