Dependence of the magnetic properties on the Mn/In flux ration in multiple stacked self-assembled (In1-xMnx)As quantum dots (QDs) was investigated. Transmission electron microscopy images showed that crystalline (In0.84Mn0.16)As QDs with symmetric single-domain particles were formed on GaAs substrates. Magnetic force microscopy (MFM) images showed that the density of the (In1-xMnx)As QDs decreased with increasing Mn/In flux ratio, and the magnetization curves as functions of the magnetic field at 5K depicted that the magnetization of the (In1-xMnx)As QDs increased. Near-field scanning optical spectroscopy spectra for the (In0.84Mn0.16)As stacked QDs showed the interband transitions from the ground electronic subband to the ground heavy-hole band, indicative of the semiconductor phase of the QDs. These results indicate that magnetic properties of (In1-xMnx)As QDs are affected by the Mn/In flux ratio. (C) 2007 Elsevier B.V. All rights reserved.