Nickel manganite thin films were prepared by chemical solution deposition from nitrate and acetate precursors on polished alumina substrates. By variation of crystallization temperature between 650 °C and 900 °C and atmosphere during cooling of the films, the morphology, phase formation and electrical properties of the films were investigated. The electrically conductive spinel phase was formed as a main phase independent of processing conditions exhibiting NTCR characteristics. Cooling down in nitrogen atmosphere favored the decomposition of the spinel phase into nickel oxide and a spinel phase with higher manganese content, but it also reduced the resistance drift of the samples. From this finding it can be deduced that a reduced oxygen partial pressure influences defect equilibria and by that decreases cation vacancy concentration. This supports the assumption that cation redistribution by a cation vacancy diffusion mechanism is a relevant mechanism of resistance drift in such thin films.
ASJC Scopus subject areas
- Keramische und Verbundwerkstoffe
- Elektronische, optische und magnetische Materialien