Nanoparticle Shape Influences the Magnetic Response of Ferro-Colloids

The interesting magnetic response of conventional ferro-colloid has proved extremely useful in a wide range of technical applications. Furthermore, the use of nano/micro- sized magnetic particles has proliferated cutting-edge medical research, such as drug targeting and hyperthermia. In order to diversify and improve the application of such systems, new avenues of functionality must be explored. Current efforts focus on incorporating directional interactions that are surplus to the intrinsic magnetic one. This additional directionality can be conveniently introduced by considering systems composed of magnetic particles of different shapes. Here we present a combined analytical and simulation study of permanently magnetized dipolar superball particles; a geometry that closely resembles magnetic cubes synthesized in experiments. We have focused on determining the initial magnetic susceptibility of these particles in dilute suspensions, seeking to quantify the effect of the superball shape parameter on the system response. In turn, we linked the computed susceptibilities to the system microstructure by analyzing cluster composition using a connectivity network analysis. Our study has shown that by increasing the shape parameter of these superball particles, one can alter the outcome of self-assembly processes, leading to the observation of an unanticipated decrease in the initial static magnetic susceptibility. © 2017 American Chemical Society.J.G.D. and S.S.K. are grateful to the financial support of the Austrian Science Fund (FWF): START-Projekt Y 627-N27. E.S.P and S.S.K. acknowledge the support of 3.1438.2017/4.6, RFBR grant 16-52-12008 and DFG ref. no. OD 18/24-1. S.S.K. would also like to acknowledge ETN-COLLDENSE (H2020-MSCA-ITN-2014, grant no. 642774). The computational results presented here have been achieved using the Vienna Scientific Cluster (VSC)