Reversible 300K Ferromagnetic Ordering in a Diluted Magnetic\n Semiconductor

The discovery of reversible 300 K ferromagnetic ordering in a diluted\nmagnetic semiconductor is reported. Switching of room-temperature\nferromagnetism between "on" and "off" states is achieved in Co2+:ZnO by lattice\nincorporation and removal of the native n-type defect, interstitial Zn.\nSpectroscopic and magnetic data implicate a double-exchange mechanism for\nferromagnetism. These results demonstrate for the first time reversible\nroom-temperature ferromagnetic ordering in a diluted magnetic semiconductor,\nand present new opportunities for integrating magnetism and conductivity in\nsemiconductor sensor or spin-based electronics devices.\n