Kim, Bo-Yun Seong, Tae-Geun Seo, In-Tae Jang, Min-Soo Nahm, Sahn Kang, Jong-Yun Yoon, Seok-Jin 2024-01-20T15:03:10Z 2024-01-20T15:03:10Z 2021-09-05 2012-04 1359-6454 https://pubs.kist.re.kr/handle/201004/129371 Amorphous (Na0.5K0.5)NbO3 (NKN) thin films were grown at 300 degrees C and subsequently annealed at 800 degrees C under Na2O, K2O and NKN atmospheres. When the annealing time was less than 50 min, K6Nb10.88O30 and Na2Nb4O11 secondary phases were formed in all the films. Moreover, they were also found in films annealed at 750 C for 180 min under NKN atmosphere, indicating that they were transient phases formed when the sintering time and temperature were not sufficient. For the film annealed for 50 min under Na2O atmosphere, an Na-excess (Na1-xKx)NbO3 (N1-xKxN) phase was formed, whereas a K-excess N1-xKxN phase was developed in the film annealed under K2O atmosphere. On the other hand, a homogeneous NKN phase was developed in the film annealed under NKN atmosphere and this was maintained after a long period (100 min) of annealing at 800 degrees C. A high leakage current density and a small dielectric constant (epsilon(r)) were observed for films annealed under Na2O and K2O atmospheres due to the evaporation of K2O and Na2O, respectively. Moreover, they exhibited a small remnant polarization (P-r) and a small coercive electric field (E-c). On the other hand, the film annealed under NKN atmosphere exhibited a very low leakage current density of 2.6 x 10(-9) A cm(-2) at 0.2 MV cm(-1) and had good ferroelectric and piezoelectric properties of epsilon(r) = 620, P-r = 11.7 mu C cm(-2), E-c = 133.8 kV cm(-1) and d(33) = 74 pm V-2 at 50 kV cm(-1). (C) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. English PERGAMON-ELSEVIER SCIENCE LTD FREE PIEZOELECTRIC CERAMICS MICROSTRUCTURE SUBSTRATE BEHAVIOR Effects of annealing atmosphere on the structural and electrical properties of (Na0.5K0.5)NbO3 thin films grown by RF magnetron sputtering Article 10.1016/j.actamat.2012.02.015 1 ACTA MATERIALIA, v.60, no.6-7, pp.3107 - 3112 ACTA MATERIALIA 60 6-7 3107 3112 scie scopus 000303952000059 2-s2.0-84862804843 Materials Science, Multidisciplinary Metallurgy & Metallurgical Engineering Materials Science Metallurgy & Metallurgical Engineering Article FREE PIEZOELECTRIC CERAMICS MICROSTRUCTURE SUBSTRATE BEHAVIOR Lead-free NKN thin film Piezoelectricity Sputtering Annealing