Experimental investigation of nearly monodispersed ternary Mn_0.5Zn_0.5Fe₂O₄ magnetic fluid

K. Parekh¹ , R. V. Upadhyay² , R. V. Mehta² , V. K. Aswal³

¹ Department of Physics, Faculty of Sciences, The M S University of Baroda, Vadodara, 390 001, India
² Department of Physics, Center for Excellence on Nanotechnology of Nanomagnetic Particles (GUJCOST), Bhavnagar University, Bhavnagar, 364 002, India
³ Solid State Physics Division, Bhabha Atomic Research Center,Anushaktinagar, Trombay, Mumbai 400 085 India

Abstract
The experimental investigations of a nearly monodispersed magnetic fluid, containing a ternary Mn_0.5Zn_0.5Fe₂O₄ (MZ5) magnetic fluid, are carried out using XRD, TEM, Small Angle Neutron Scattering (SANS) and a SQUID magnetometer. The XRD and TEM measurements give the particle size to be 7.5 and 8.4 nm respectively, and confirms the single phase cubic spinel structure. The size distribution retrieved from TEM is found to be very narrow ( < 10%). Room temperature magnetic measurement fits with the Langevin's function modified for the particle size distribution as well as for the particle-particle interaction parameter. M(H)-measurements as a function of field for different temperatures show that the system is superparamagnetic at room temperature and develops coercivity at 5 K. Figs 4, Refs 12.