Why does an electromagnet with a steel core remain magnetic even with the current turned of?

An electromagnet with a steel core can remain magnetic after the current is turned off due to a phenomenon called magnetic hysteresis. Steel, being a ferromagnetic material, has the ability to retain some of the magnetic alignment of its domains even when the external magnetic field (from the current) is removed. This residual magnetism is a result of the energy lost in the process of magnetization and the material's internal structure, which can "trap" some of the magnetic orientation. However, the strength and duration of this residual magnetism can vary depending on the type of steel and its treatment.