Quasiferromagnetism in semiconductors

Ferromagnetic hysteresis has been observed at room temperature in materials not consisting of elements commonly associated with ferromagnetism, such as Co, Ni, Fe, or Mn-containing alloys. In particular, we report on magnetic hysteresis seen in silicon prepared by two different techniques: ion implantation (Si and Ar) and neutron irradiation. Because the material investigated contains no ferromagnetic elements, we tentatively call it "quasiferromagnetic." The paramagnetic defects present in these materials were investigated using electron paramagnetic resonance. We suggest that these defects are one of the factors responsible for the observed macroscopic magnetic hysteresis loop. (c) 2006 American Institute of Physics.