Phase transitions in tungsten trioxide at low temperatures
Capacitance and electrical resistivity measurements have been made on stoichiometric and on oxygen-deficient tungsten trioxide crystals from 4.2 to 300°K. X-ray oscillation and rotation photographs were made on single crystals of both materials near 200 and 300$sup 0$K. Capacitance and resistivity anomalies identify phase transitions near 40, 65, 130, 220, and 260°K in stoichiometric WO 3. Resistivity anomalies occur near 80, 130, 220, and 260$sup 0$K in oxygen-deficient tungsten trioxide. Results of capacitance measurements suggest that the transformation at 130°K of a low-temperature phase to a high temperature phase of stoichiometric WO 3 is associated with a doubling of the c-parameter of the unit cell. Resistivity measurement results establish probable conduction mechanisms in each phase of stoichiometric and of oxygen-deficient tungsten trioxide, and show that oxygen-deficient tungsten trioxide undergoes a semiconductor-to-metal transition near 220°K. Electronic phenomena that do not appear to be associated with structural phase transformations are observed near 16°K in stoichiometric WO 3.
- Research Organization:
- Pitman--Dunn Lab., Philadelphia
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-33-003461
- OSTI ID:
- 4152191
- Journal Information:
- Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 1 Vol. 15; ISSN 0022-4596
- Publisher:
- Elsevier
- Country of Publication:
- United States
- Language:
- English
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