Figure 3

ZFC/FC magnetization and hysteresis loops. (a) Magnetization curves with an applied field of 50 Oe after ZFC/FC for the Mn-implanted Ge. The lower branches are ZFC curves, while the upper branches are FC curves. With increasing fluence, the Mn₅Ge₃ nanocrystals are growing in size, resulting in a higher blocking temperature. The curves are vertically shifted to increase the visibility. (b) Hysteresis loops measured at 5 K for Mn-implanted Ge with different fluence, and the inset shows the magnetization at 300 K for sample 5E16.