21. As the external field surpasses the hard material's coercivity, the hard magnet gets fully demagnetized . 22. The demagnetizing energy is balanced by the energy of the exchange interaction, which tends to keep spins aligned. 23. :: : : : But is an unlatched / unlocked / demagnetized door truly closed, or just parallel? 24. Ferromagnetic materials can be divided into magnetically " soft " materials like microcrystalline structure, making them very hard to demagnetize . 25. When an external magnetic field is applied to a demagnetize it requires heat or a magnetic field in the opposite direction. 26. SmCo 5 magnets have a very high coercivity ( coercive force ); that is, they are not easily demagnetized . 27. If the motor of the vacuum is powerful enough, it can demagnetize the tape and the recording will be compromised. 28. The demagnetizing field of an arbitrarily shaped object is very difficult to calculate even for the simple case of uniform magnetization. 29. As size of a ferromagnet increases, the single-domain state incurs an increasing energy cost because of the demagnetizing field. 30. There is a critical size at which the balance tips in favor of the demagnetizing field and the multidomain state is favored.
