Size-Controlled Ex-nihilo Ferromagnetism in Capped CdSe Quantum Dots

M. S. Seehra; P. Dutta; S. Neeleshwar; Y.-Y. Chen; C.-L. Chen; C.-L. Dong; S.-W. Chou; Chia-Chun Chen; C.-L. Chang

Size-Controlled Ex-nihilo Ferromagnetism in Capped CdSe Quantum Dots

Date

2008-05-05

Authors

M. S. Seehra

P. Dutta

S. Neeleshwar

Y.-Y. Chen

C.-L. Chen

C.-L. Dong

S.-W. Chou

Chia-Chun Chen

C.-L. Chang

Publisher

Wiley-VCH Verlag

Abstract

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 k2χ 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 µ = 0.0075 µB per Cd surface atom.