Evidence of Ferrimagnetism in Fe-Doped CdSe Quantum Dots

Abstract

Two interacting spin sublattices are observed for 5.1 nm Fe (4.6%) CdSe quantum dots giving rise to a superparamagnetic material with a blocking temperature of ∼90 K. The field- and temperature-dependent 57Fe Mössbauer spectra reveal that the observed magnetic properties arise from the antiparallel alignment of two dissimilar, Fe(III)-based spin-lattices. Comparison of the experimental data with density functional theory calculations suggests the formation of an ordered minor and major spin-lattice within the quantum dot (QD) can be ascribed to the antisite pair formation of the Fe(III) centers around a cadmium vacancy.