Exchange spring magnet
The magnetostatic energy is the energy stored in the field generated by a material's magnetic moments. The magnet's field reaches its maximum intensity if all the magnetic moments orient in one direction; this is what occurs in a hard magnet. In order to prevent building up the magnetic field, sometimes magnetic moments tend to form loops. That way, the energy stored in the magnetic field can be constrained; this is what occurs in a soft magnet. What determines whether a magnet is hard or soft is the dominant term of its magnetic energy. For hard magnets, the anisotropy constant is relatively large, making the magnetic moments align with easy axis. The opposite case applies to soft magnets, in which the magnetostatic energy is dominant.
Pulsed field magnet
A pulsed field magnet is a strong electromagnet which is powered by a brief pulse of electric current through its windings rather than a continuous current, producing a brief but strong pulse of magnetic field. Pulsed field magnets are used in research in fields such as materials science to study the effect of strong magnetic fields, since they can produce stronger fields than continuous magnets. The maximum field strength that continuously-powered high-field electromagnets can produce is limited by the enormous waste heat generated in the windings by the large currents required. Therefore by applying brief pulses of current, with time between the pulses to allow the heat to dissipate, stronger currents can be used and thus stronger magnetic fields can be generated. The magnetic field produced by pulsed field magnets can reach between 50 and 100 T, and lasts several tens of milliseconds.