Magnetic response of Mn-doped amorphous porous Ge fabricated by ion-implantation

Ge substrates of (1 0 0) orientation were irradiated with 100 keV Mn ions (2 × 1016 at./cm2) at a temperature of 190 °C. Pronounced swelling of the irradiated material up to 150 nm, associated with the formation of a Mn-doped amorphous porous Ge layer, is investigated by scanning electron microscopy and X-ray photoelectron depth profiling. Magneto-optical Kerr effect hysteresis loops have been used to characterize the magnetic properties of the obtained sample. The details of the hysteresis loops reveal that the ferromagnetic property of the sample up to ∼20 K and the subsequent strong non-linear paramagnetic response must be ascribed to Mn atoms dispersed in the amorphous porous implanted layer.