Accession Number:

AD0262457

Title:

ELECTRON SPIN RESONANCE IN SEMICONDUCTING RUTILE

Descriptive Note:

Corporate Author:

WESTINGHOUSE ELECTRIC CORP PITTSBURGH PA

Personal Author(s):

Report Date:

1961-06-01

Pagination or Media Count:

1.0

Abstract:

The electron spin resonance spectra of a number of samples of single-crystal, oxygen-deficient rutile have been examined in the helium temperature range. Room temperature resistivities c axis ranged from 0.76 to 94 ohm cm. The method of reduction is found to be a determining factor in the nature and temperature dependence of the spectra. The simple spectrum already reported for a 10 ohm cm sample, is found only after reduction in hydrogen followed by partial reoxidation. This spectrum degenerates as the temperature is raised to 12 K to be replaced by a single line which corresponds to the motionally narrowed line observed in lower resistance 0.76 ohm cm samples. Reduction in vacuum leads to distinctly different spectra with different temperature dependence but with similar g values. Measurements of resistivity vs temperature indicate higher activation energies for vacuum-reduced samples. Possible models for the observed paramagnetic centres are put forward and discussed in relation to the defect structure and electrical properties. The low temperature spectra of niobium- and tantalum-doped rutile indicate that the donor centres in these materials are Nb4 and Ta4 rather than Ti3. Author

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE