Use of a Natural Clinoptilolite Monolith as Thermistor

Geomorphic clinoptilolite, a mechanically and thermally stable mineral substance, has very useful electrical properties due to the presence of extra-framework cations in the crystal structure.Indeed, owing to the electrical transport that alkaline-earth metal cations may give, this ceramic material behaves like an electrical insulator at room temperature, while it changes to an electrical conductor with the increasing of temperature.Such unusual electrical property of clinoptilolite can be advantageously exploited for a number of functional applications in the industrial field like, for example, thermal sensors, electrical/thermal switches, thermistors, etc.Here, the capability of a simple natural clinoptilolite monolith to switch from electrical insulator to conductor under fast and slow temperature changes has been investigated by a.c.electrical transport measurements.