Size-controlled Ex-nihilo ferromagnetism in capped CdSe quantum dots

Hysteresis loops in D = 1.8 nm CdSe-TOPO nanoparticles show ferromagnetism at 5 K and 300 K. Charge transfer from Cd to the Cd-O bond is shown by arrow in the Fourier transforms amplitudes of the EXAFS k(2)chi data at the Cd K-edge in the smaller 2.8 and 4.1 nm particles. This charge transfer produces holes in the Cd 4d band yielding ferromagnetism varying as 1/D with magnetic moment mu = 0.0075 mu(B) per Cd surface atom.