Magnetic devices incorporating magnetic composite materials are disclosed. A tunable magnetic device includes magnetic composite material and a magnetic field source. The magnetic composite material includes an insulator and magnetic material embedded in the insulator. The magnetic material has a remanent magnetization. The magnetic field source is operable to apply a magnetic field to the magnetic composite material in order to change the remanent magnetization of the magnetic material. A magnetic device for detecting a magnetic pulse includes magnetic composite material and a sensor. The magnetic composite material includes an insulator and magnetic material embedded in the insulator. The magnetic material has a remanent magnetization. The remanent magnetization changes when the magnetic composite material receives the magnetic pulse. The sensor is positioned to determine the remanent magnetization of the magnetic material. The device detects the magnetic pulse based on a change in the remanent magnetization of the magnetic composite material.