Synthesis, phase characterization, and properties of chemical solution-deposited nickel manganite thermistor thin films

Heidi Schulze, Jing Li, Elizabeth C. Dickey, Susan Trolier-Mckinstry

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41 Scopus citations

Abstract

Nickel manganite spinel thin films prepared by chemical solution deposition exhibit negative temperature coefficient of resistance (TCR) values between -3.3 and -4.5%/K. In contrast to bulk thermistors, dense films could be prepared completely within the spinel phase field. Thus, decomposition into the NiO phase and a Mn-rich spinel, which is problematic in bulk ceramics, is minimized in thin films. For films prepared outside of the single-phase field, phase separation cannot always be detected using X-ray diffraction. In such cases, transmission electron microscopy is useful in identifying decomposition. It is found that the lattice parameters for films with compositions ranging between Mn/(Mn+Ni)=0.14 and 0.77 are smaller than the values reported for nickel manganite spinels, suggesting cation deficiency. Single-phase spinel films are compared with single-phase bixbyite films synthesized between 630° and 930°C. The bixbyite phase exhibits lower TCR and lower resistivity (TCR=-3.1 to -3.3%/K and resistivity values=400-1600 Ω·cm) compared with spinel (TCR=-3.6 to -4.1%/K and resistivity values=3500-21 000 Ω·cm). Composite films (achieved by controlling the pyrolysis to create a low local pO 2 during annealing) show intermediate values (TCR=-3.0 to -3.8%/K and resistivity values=470-6600 Ω·cm).

Original languageEnglish (US)
Pages (from-to)738-744
Number of pages7
JournalJournal of the American Ceramic Society
Volume92
Issue number3
DOIs
StatePublished - Mar 2009

All Science Journal Classification (ASJC) codes

  • Ceramics and Composites
  • Materials Chemistry

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