Low-current Noise Measurement Techniques

The noise of a resistive sample is a measurable physical property. The noise signature can depend on such variables as the materials used in preparing a sample and the method used to prepare it. A versatile experimental technique is needed to measure these noise signatures, one which can be applied to any form of resistive structure. In addition, many samples with unique physical properties, such as tunnel junctions, are destroyed by large currents. We require a method which is sensitive enough to measure noise at low currents. Such a technique is explained here.