Discovery Teaching Labs - Heat Capacity Measurement of Vanadium Oxide Powder

Heat Capacity Measurement of Vanadium Oxide Powder
PPMS® VersaLab®

The objective of this educational module is to measure the heat capacity of vanadium dioxide (VO2), a material that exhibits a structural phase transition at 340K that coincides with a transition from a low-temperature monoclinic insulating phase to a high temperature rutile metallic phase. VO2 is a well-known correlated electron material that is being actively investigated to elucidate the relative importance of structural changes versus electronic correlations as the fundamental cause of the transition. The insulator-to-metal transition in VO2 is first order resulting in a large latent heat, which can be measured using the heat capacity option of the VersaLab.

Several items are needed for this experiment, which include:

  • VO2 powder, available from Alfa Aesar.
  • Apiezon H grease. Importantly, the specific heat of N grease is strongly temperature dependent above 200K, so H grease is recommended to minimize errors.
  • Grease applicator which can be the wooden end of a cotton swab.
  • A microscope to facilitate the application of the grease and sample.
  • A precision scale with 0.1 mg or better resolution.
  • Weigh boats or wax paper for handling the VO2 powder.
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