<span style="mso-bidi-language:HI">Mossbauer, X-ray and magnetization studies of Ni_0.5Zn_0.5Al_xFe_2-xO₄ system </span>

Abstract

<span style="mso-bidi-language:HI">The structural and magnetic properties of the mixed spinel system Ni_0.5Zn_0.5Al_xFe_2-xO₄ (x=0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) have been investigated by X-ray diffraction, magnetization and Mossbauer measurements. The variation of Mossbauer

<span style="mso-bidi-language:HI">parameters, lattice parameters and crystalline size of the products formed with variation in the composition of Fe and Al ratio has been studied. The studies confirm the formation of nano-size ferrite particles. It is observed that lattice parameters

<span style="mso-bidi-language:HI">decrease, with increasing aluminium concentration. A ferromagnetic relaxation occurs when <i>x </i>is increased to 0.6, which is followed by weak paramagnetic transition. With further increase of <i>x </i>to 1.0 the system again shows weak ferromagnetism. The decrease in magnetic hyperfine field with increase in Al concentration has been explained on the basis of super transferred hyperfine field. The variation of the saturation magnetic moment per formula unit measured at 300 K decreases

<span style="mso-bidi-language:HI">with Al concentration <i>x, </i>suggesting the decrease in ferromagnetic behaviour. These observations indicate the existence of a non-collinear structure in a nano-particles ferrite system. The non-collinear structure in this system is also verified by Neel's

<span style="mso-bidi-language:HI">two sub-lattice model.

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