About cookies on this site Our websites require some cookies to function properly (required). In addition, other cookies may be used with your consent to analyze site usage, improve the user experience and for advertising. For more information, please review your options. By visiting our website, you agree to our processing of information as described in IBM’sprivacy statement. To provide a smooth navigation, your cookie preferences will be shared across the IBM web domains listed here.
Paper
Heat-capacity measurements on granular aluminum
Abstract
We have measured the heat capacity of a series of films of aluminum in Al2O3, with normalstate resistivities N from 2 × 10-5 cm to 4 × 10-2 cm. The lattice heat capacity is greater than for the separate bulk constituents, but there is no evidence for a change in the electronic specific heat capacity. The specimens become superconducting with a heat-capacity transition which is BCS-like for low N and diminishes as N becomes greater than 10-3 cm, until it is no longer observable for the highest N. We conclude that as N increases the grains become decoupled. The size of the grains is such that thermodynamic fluctuations prevent the existence of bulk superconducting properties when they are isolated. © 1980 The American Physical Society.