Special Magnetic Measurement Techniques

Abstract

Various magnetic measurement techniques, not generally applicable to all magnetic systems, are reviewed. Specific examples of direct measurement techniques considered include difference or differential magnetization measurements with static or pulsed fields and ac (periodic) variations of magnetization M or temperature T (∂M/∂T, ∂T/∂H, ∂M/∂H). Special emphasis is given to ac techniques, because commercial ac electronic processing equipment now permits a wide variety of sophisticated investigations to be readily accomplished. A number of indirect techniques are briefly discussed, such as the numerous magnetic resonances which permit microscopic local field evaluations. Limitations of these indirect techniques and some of the assumptions generally made when applying them to deduce magnetic properties are emphasized. A short review of the production of high magnetic fields in superconducting, high‐power water‐cooled, and pulsed‐field solenoids is given, and production of very low fields is also briefly discussed. The last section considers measurement of magnetic fields, mainly high fields in low‐temperature environments, and very low fields.