Microstructure and electrical properties of Ni-Zn manganite ceramics

Nickel zinc manganite ceramics Mn2.34Ni0.66ZnxO4 (0 less than or equal to x less than or equal to 1.02) were investigated using structure, microstruct ure and electrical property interrelationships. The resistivity increased w ith zinc content whereas the activation energy remained constant. The drift of resistivity under thermal constraint, commonly observed in NTC thermist ors was almost nil when the zinc content was sufficiently high (x greater t han or equal to 0.7). Homogeneous microstructures and high densities were o btained when the ceramics were prepared from fine powders. The Ni/Zn/Mn/O s ystem prepared by 'chimie douce' has interesting NTC properties for industr ial applications. (C) 2000 Elsevier Science Ltd. All rights reserved.