Articles
  • Preparation and electrical properties of nickel manganite Ni0.79Mn2.21O4 ceramics for NTC thermistors
  • Hye-Rin Junga, Sung-Gap Leea,*, Kyeong-Min Kima, Min-Su Kwona and Young-Gon Kimb
  • a Dept. of Materials Engineering and Convergence Technology, RIGET, Gyeongsang National University, Jinju 52828, Korea b Dept. of Electronics, Chosun college of Science and Technology, Gwangju 61453, Korea
Abstract
Ni0.79Mn2.21O4 ceramics were prepared using the mixed-oxide method. All specimens displayed the typical XRD patterns of a single-phase cubic polycrystalline structure. The average grain size of the specimen sintered at 1200 oC was approximately 6.65 μm. All specimens exhibited the typical NTC thermistor characteristic where the electrical resistance exponentially decreases with an increase in temperature. The conduction process can be explained well by the nearest neighbor hopping (NNH) mechanism. The NTC property, activation energy, B25/50 constant and resistivity at room temperature of the Ni0.79Mn2.21O4 specimen sintered at 1150 oC were -4.2%/oC, 4024 K, 0.329 eV and 3360 Ω·cm, respectively. These values are good enough to be applied to NTC thermistor devices.

Keywords: Ni-Mn oxide, Sintering temperature, Structural properties, Electrical properties.

This Article

  • 2017; 18(5): 357-360

    Published on May 31, 2017