Nanocrystalline Nickel Zinc ferrites of composition Ni0.5Zn0.5Fe2-xAlxO4 (where x = 0.00-0.25) have been synthesized by the nitrate citrate auto combustion technique. These samples were sintered at 1000 degrees C. All the samples were characterized by XRD, Infrared spectroscopy (IR), Scanning Electron Microscopy (SEM) and Vibrating sample magnetometer (VSM). The XRD patterns confirm the spinel structures. The lattice constant decreases with increasing aluminum concentration which is due to the replacement of Fe3+ with Al3+ ions. Cation distribution proposed from XRD and IR. It is observed that Al3+ ions are distributed into tetrahedral and octahedral sub-lattices. The saturation magnetization decreases from 70.53 emu gm(-1) to 40.19 emu gm(-1) with the increase of aluminum. This decrease in magnetization is ascribed to the presence of the non-collinear spin (canted spin) structure in octahedral sub-lattice. (C) 2014 Elsevier B.V. All rights reserved.