Crystallization Atmosphere and Substrate Effects on the Phase and Texture of Chemical Solution Deposited Strontium Niobate Thin Films

Abstract

Strontium niobate (Sr:Nb = 1:1) thin films were prepared via chemical solution deposition on (001)‐oriented SrTiO3, (001)p‐oriented LaAlO3, (0001)‐oriented sapphire, and polycrystalline alumina substrates. Crystallization in oxygen at 1000°C yielded Sr2Nb2O7 films on all substrates with strong (010) orientation. Films on LaAlO3 and SrTiO3 single‐crystal substrates possessed a small amount of preferred in‐plane orientation, whereas films prepared on sapphire and polycrystalline alumina substrates were fiber textured. Films crystallized at 900°C in a low oxygen atmosphere (~10−21 atm pO2) formed a randomly oriented polycrystalline perovskite, SrNbO3−δ on all substrates. A similar set of films crystallized at 900°C at a slightly higher oxygen partial pressure (~10−15 atm pO2) was comprised of Sr2Nb2O7 and SrNbO3−δ phases, exposing the dependence of phase formation on oxygen partial pressure. When subjected to a high‐temperature anneal in oxygen, the SrNbO3−δ phase is shown to transform into Sr2Nb2O7, however, Sr2Nb2O7 did not significantly reverse transform into SrNbO3−δ after annealing in low oxygen partial pressure atmospheres.

Synthesis and Characterization of Eu3+‐Doped Transparent Glass–ceramics Containing Nanocrystalline SrIINbIVO3

“…[9][10][11][12] Ceramics with composition Sr x NbO 3 were first investigated in the 1950s 13,14 and it was reported that a single-phase cubic perovskite is formed for 0.70 < x < 0.95 and these perovskites are found to be metallic conductors down to 4 K. Since the last decade, the perovskites SrMO 3 (M = Ti, V, Zr, and Nb) attract much attention from physicists and material scientists because of the unusual combination of their magnetic, electronic, and transport properties. [15][16][17][18][19] Among these the preparation of Sr II Nb IV O 3 crystal phase with cubic perovskite structure might be difficult as Nb ion prefers to exist in 5+ oxidation state rather than 4+ oxidation state. 20 In recent past, it was clearly demonstrated the use of Sr 1Àx NbO 3 (0.1 ≤ x ≤ 0.2) as an effective photocatalyst.…”

Glass‐Like Thermal Conductivity of (010)‐Textured Lanthanum‐Doped Strontium Niobate Synthesized with Wet Chemical Deposition

“…At this defect density (9 slabs of the n = 5 phase versus 34 slabs of n = 4 present within the left image), we calculate that there is a small amount of oxygen reduction by δ = 0.05 in the Sr 2− x La x Nb 2 O 7−δ samples. To confirm our results were not sensitive to this low level of reduction, an additional sample ( x = 0.1, approximately 220 nm thick) was prepared through CSD, but done so in oxidizing atmospheres to discourage the formation of the n = 5 slabs …”

“…Minority peaks associated with the 002 and 151 reflections were also observed, but constituted less than 3% of the diffracting volume based upon comparison of measured intensities and those expected from a random powder pattern. In previous work these films were shown to possess a random in‐plane orientation and therefore are fiber‐textured. Also, while we utilize single crystalline substrates in this study, (010)‐fiber texture was identified on non‐lattice‐matched and polycrystalline substrates, demonstrating a preferred (010) out‐of‐plane orientation regardless of substrate, which makes this technique/materials system uniquely manufacturable for thermal applications.…”

“…(0 k 0)‐oriented fiber‐textured strontium niobate and lanthanum‐doped strontium niobate films were prepared on SrTiO 3 substrates as described in previous work . In short, a chelate‐based CSD approach was used where strontium or strontium and lanthanum acetates were dissolved in propionic acid and niobium butoxide was chelated with six molar equivalents of acetic acid.…”

“…(0k0)-oriented fiber-textured strontium niobate and lanthanum-doped strontium niobate films were prepared on SrTiO 3 substrates as described in previous work. 27 In short, a chelate-based CSD approach was used where strontium or strontium and lanthanum acetates were dissolved in propionic acid and niobium butoxide was chelated with six molar equivalents of acetic acid. The appropriate amount of the dissolved acetates was added to the niobium precursor, as measured by constituent masses, and the solutions were diluted to 0.15M with anhydrous ethanol.…”