  Phase transitions are caused by varying temperature, or pressure, or magnetic
field. The observation of 1st order magneto-structural transitions has created
application possibilities based on magnetoresistance, magnetocaloric effect,
magnetic shape memory effect, and magneto-dielectric effect. Magnetic field
induced transitions, and phase coexistence of competing magnetic phases down to
the lowest temperature, gained prominence over a decade ago with theoretical
models suggesting that the ground state is not homogeneous. Researchers at
Indore pushed an alternative view that this phase coexistence could be due to
glasslike kinetic arrest of a disorder-broadened first-order magnetic
transition between two states with long-range magnetic order, resulting in
phase coexistence down to the lowest temperatures. The CHUF (cooling and
heating in unequal field) protocol created at Indore allows the observation of
devitrification, followed by melting. I show examples of measurements
establishing kinetic arrest in various materials, emphasizing that glasslike
arrest of 1st order magnetic transitions may be as ubiquitous as glass
formation following the arrest of 1st order structural transitions.
