Electrical Properties of Mn_3−xCo_xO₄ (0 ≤ x ≤ 3) Ceramics: An Interesting System for Negative Temperature Coefficient Thermistors

Abstract

Single-phase spinel manganese cobalt oxides Mn 3Àx Co x O 4 dense ceramics were prepared for the first time and their structural/electrical property relationships characterized. The electrical properties, that is, the resistivity at 25°C, the energetic constant, and the resistance drift at 125°C, were determined and correlated with the cation distribution. Finally, the electrical characteristics of the Mn 3Àx Co x O 4 system were compare'd with other important classes of manganese-based spinel oxides, Mn 3Àx Ni x O 4 and Mn 3Àx Cu x O 4 , already commercialized as negative temperature coefficient (NTC) thermistors. The high values of energetic constant and low resistivities observed in Mn 3Àx Co x O 4 ceramics present a promising interest for such industrial applications. *tenailleau@chimie.ups-tlse.fr

Conduction mechanism in cobalt rich Co3-xMnxO4 (0.1 ≤ x ≤ 1.0) spinel oxide ceramics

“…These observations are in close agreement to those reported results on Co3-xMnxO4 ceramics prepared by spark plasma sintering [8,11]. The authors [11] suggest that the observed trend and changes in the electrical resistivity with varying Mn content in the range (0.1 < x < 0.…”

“…For device point of view, electronic properties of solids are tremendously important for applications in storage of data, microelectronics, communication technologies and other related fields. An earlier report on singlephase Co3-xMnxO4 ceramics shows their negative temperature coefficient [8], multiferroic [9] and universal dielectric [10] nature. In the literature a number of studies have been devoted to manganese rich phases of Co3-xMnxO4 (x ≥ 1.5), and very few studies have been focused towards the cobalt rich phases with x ≤ 1.0.…”

Thermal Treatment of Aerosol Deposited NiMn2O4 NTC Thermistors for Improved Aging Stability

“…Hence, the NTCR characteristics should be especially affected in this temperature range, as it is observed in Figure 10b. Looking at the aging behavior, a major change can be seen within the first 100 h. This behavior is typical for NTCR ceramics and has been observed many times [23,27,48]. The as-deposited samples showed large changes in B and R 25 values for both Au and AgPd.…”

“…In addition to the reproducibility of the NTCR characteristics (resistance at 25 °C, R 25 ; specific resistance at 25 °C, ρ 25 ; and the B constant), long-term stability also plays a decisive role. It is known from the field of NTCR ceramics that most thermistor ceramics undergo a change (usually an increase) in electrical resistance over time and under thermal stress, which is referred to as aging [23,24,25]. The degree of aging or “aging resistance” is determined by the composition and the thermal history.…”

Electrical Properties of ZnxMn3-xO4Ceramics for Application as IR Detectors

“…They are important technological materials used as negative temperature coefficient (NTC) thermistors owing to their interesting electrical properties [2][3][4]. The electrical conduction mechanism of M x Mn 3-x O 4 spinel materials is described as a hopping mechanism resulting from electron movement between neighboring Mn ions in the octahedron-adjacent sites.…”