Fig. 4From: Thermoelectric Properties of Nano-Meso-Micro β-MnO2 Powders as a Function of Electrical ResistanceExperimental X-ray diffraction results of samples S4, S5, S6, S7, and S8. Sample S4 was the as-received sample, while samples S5, S6, S7, and S8 were prepared by hand grinding with a mortar and pestle for 15, 30, 45, and 60 min., respectivelyBack to article page