SPECIFIC-HEAT SPECTROSCOPY - ORIGINS, STATUS AND APPLICATIONS OF THE 3-OMEGA METHOD

We review the technique of 'specific heat spectroscopy,' of Birge and Nagel. The technique, also called the '3 omega method' in the literatu re, is nonadiabatic; it is based on thermal diffusion into a thick sam ple from a thin metallic him that serves simultaneously as heater and thermometer. Specific heat spectroscopy allows one to measure the dyna mic specific heat of a liquid or solid over a frequency range exceedin g 6 decades, and simultaneously the thermal conductivity over a more l imited frequency range. Designed to study supercooled liquids near the glass transition, specific heat spectroscopy has also been used to st udy phase transitions and biological systems. (C) 1997 Elsevier Scienc e B.V.