Chapter 19 - Magnetism - Learning Path Questions and Exercises - Conceptual Questions - Page 690: 28

One can destroy or reduce the magnetic field of a permanent magnet by hitting or heating it like by hammering the magnet or heating above a particular temperature or by applying pressure or dropping it on a hard surface. Another method is to apply AC current to demagnetize the magnet.

One can destroy or reduce the magnetic field of a permanent magnet by hitting or heating it like by hammering the magnet or heating above a particular temperature or by applying pressure or dropping it on a hard surface. Another method is to apply AC current to demagnetize the magnet.