Growth and field dependent dielectric properties of epitaxial Na0.5K0.5NbO3 thin films

Abstract

Na 0.5 K 0.5 NbO 3 thin films have been grown on LaAlO3(001) substrates using rf magnetron sputtering from a Na and K enriched target. X-ray diffraction showed that the films are epitaxial with mosaic broadening as narrow as 0.044°. Interdigital Au finger electrodes were photolithographically defined on the film surfaces. The dielectric properties of these interdigital capacitors were measured at 1 MHz from room temperature down to 50 K. The capacitor showed 35% tunability at room temperature and a loss tangent of 0.007 without dc bias applied. The loss decreased further with increasing dc bias. For lower temperatures, the capacitance exhibited a broad maximum at ∼200 K, which is possibly linked to a phase transformation of the Na0.5K0.5NbO3 film.

Hydrothermal synthesis of KNbO3 and NaNbO3 powders

“…NaNbO 3 does, however, form a solid solution with KNbO 3 that is ferroelectric at room temperature and has recently attracted attention as a promising component for nonvolatile memory devices, actuators, and microsensors. 11,12 Although NaNbO 3 powders are also synthesized in this study, the main focus is on hydrothermally synthesized KNbO 3 . One issue addressed is the variation in the amount of reaction products often recovered in the hydrothermal synthesis of KNbO 3 powder, as mentioned earlier.…”

Lead-Free KNN-Based Piezoelectric Materials

“…In 1989, Margoline et al deposited KNN films on stainless steel substrates [96]. Some years later, several papers concerning with deposition of the KNN films by sputtering were reported including the articles by Wang et al [96] Kim et al [89] and Lee et al [90].…”

“…Some years later, several papers concerning with deposition of the KNN films by sputtering were reported including the articles by Wang et al [96] Kim et al [89] and Lee et al [90]. The saturation polarization, remnant polarization, and coercive field of K 0.48 Na 0.52 NbO 3 thin films with 300 nm thickness on Pt/Ti/SiO 2 /Si substrates were 42 mC cm À2 , 22.5 mC cm À2 , and 90 kV cm , À1 respectively [89,90].…”

A facile synthesis of NaNbO3 powders by decomposition of ammonium niobium oxalate with sodium salt at low temperature

“…NN generally exhibits antiferroelectric properties at room temperature; however, it easily becomes ferroelectric materials by addition of other alkaline niobates, such as KNbO 3 and LiNbO 3 [8][9][10][11][12]. NN is a dielectric material [13,14].…”