Fabrication and Electrical Properties of Mn–Ni–Co–Cu–Si Oxides Negative Temperature Coefficient Thermistors

The microstructure and electrical properties of Mn–Ni–Co–Cu–Si oxides negative temperature coefficient (NTC) thermistors were studied. The as‐sintered (Mn 1.62 Ni 0.72 Co 0.57− x Cu x Si 0.09 )O 4 (0≤ x ≤0.12) and (Mn 1.2 Ni 0.78 Co 0.87− x Cu 0.15 Si x )O 4 (0≤ x ≤ 0.15) ceramics showed the solid solutions of Mn–Ni–Co–Cu–Si oxides with a cubic spinel structure. The addition of SiO 2 led to an increase in the temperature coefficient of resistivity. This demonstrates that the SiO 2 addition is desirable for developing highly sensitive NTC thermistors. In addition, the resistivity and the temperature coefficient of resistivity for (Mn 1.62 Ni 0.72 Co 0.57− x Cu x Si 0.09 )O 4 and (Mn 1.2 Ni 0.78 Co 0.87− x Cu 0.15 Si x )O 4 NTC thermistors were controlled by changing the composition.