Thermal boundary resistance at metal-epoxy interfaces

Measurements of the thermal impedance across copper-epoxy-copper sandwiches have been made over a temperature range of 0.05--10 K. The data are consistent with the suggestion that only low-frequency phonons contribute to thermal transport across the sandwich. As a result the apparent thermal boundary resistance at the interfaces may be a factor of 100 larger than calculated from the theory of Little. A similar behavior should be observed whenever an amorphous material is involved