Thermoelectric Properties of Nano-Meso-Micro β-MnO2 Powders as a Function of Electrical Resistance

摘要

Particle sizes of manganese oxide (β-MnO~(2)) powders were modified by using a mortar and pestle ground method for period of times that varied between 15–60?min. Particle size versus ground time clearly shows the existence of a size-induced regime transition (i.e., regime I and II). Thermoelectric properties of β-MnO~(2) powders as a function of electrical resistance in the range of R ~( P )?=?10 - 80 Ω were measured. Based on the data presented, we propose a model for the β-MnO~(2) system in which nanometer-scale MnO~(2) crystallites bond together through weak van der Waals forces to form larger conglomerates that span in size from nanometer to micrometer scale.