The effect of manganese substitution to gallium on the physical properties of MgGa2−xMnxO4 spinel type ceramic thermistors

Structural, electric and magnetic properties of MgGa2−xMnxO4 based spinel type ceramic compounds have been studied. The samples, prepared by a solid state reaction method, were characterized by X-ray diffraction (XRD), temperature dependent resistivity measurements ρ(T) and magnetic measurements M(T). Mono-phase solid solutions were obtained for all samples in which magnetic ions interact antiferromagnetically at low temperature. For all samples NTC type behaviour is evidenced. The sensitivity range of these thermistors can be tuned by varying Mn content. The values of the effective magnetic momentum (μeff) seem to confirm the well-known electron “hopping” mechanism of electrical conduction, which is believed to act in this kind of materials.