International Journal of Scientific Research and Engineering Studies (IJSRES) Volume 2 Issue 10, October 2015 ISSN: 2349-8862 www.ijsres.com Page 51 Effect Of Diamagnetic Mg Substitution On Structural And Magnetic Properties Of Ni 2 z Hexaferrite Suhasini Dafe Maheshkumar Salunkhe Department of Physics, Institute of Science, RT Road, Nagpur, Maharashtra, India Abstract: Z-type hexaferrite samples with substituted diamagnetic Mg 2+ ion, Sr 3 Mg x Ni 2-x Fe 24 O 41 (x = 0, 0.2, 0.4, 0.6, 0.8, 1, 1.2, 1.4, 1.6, 1.8, 2), were prepared by the ceramic process sintered at temperature 1250°C for 6 h. The thermal, structure and magnetic properties were investigated by TG- DTA, XRD and VSM techniques. XRD analysis estimate the linear increase in the lattice parameter with Mg 2+ substitution. Variation in magnetization mainly results from site distribution of non- magnetic ions at different crystallographic sites. Coercivity was found to be affected by the change in saturation magnetization and magnetocrystalline anisotropy with Mg 2+ substitution. Long time grinding of the initial powers found useful for obtaining single phase Z-type hexaferrite. Keywords: Z-type, TG-DTA, bulk density, saturation magnetization. I. INTRODUCTION There has been a growing interest in Z-type hexaferrite for application in producing MLCI [1]. The most commonly used materials in chip inductors for high-frequency applications are NiCuZn ferrites, [2] NiCuZn ferrites typically exhibit severe property changes above 200MHz due to the Snoek limit [3]. Z-type hexaferrite is increasingly considered as an ideal candidate for MLCI because it has high performance in hyper-frequencies of 100–1000 MHz. Particularly its high cut-off frequencies up to the 3 GHz region, compared with the spinel Ni–Zn–Cu ferrites, make it useful for MLCI [4]. Unit cell of Z hexaferrite consists of 44 atomic layers which pile up to the c-axis. This structure may be described as a stack of six kinds of blocks, R, S, T, R*, S* and T*, where R, S and T are independent blocks and the asterisk indicates the same stack but rotated 180  around the c-axis. The stacking order is RSTSR*S*T*S* [5]. Here S is a two-layer building unit (Fe6O8)2+ , R is a three-layer block of composition (BaFe6O11)2- and T consists of the four-layer unit (Ba2Fe8O14) [6, 7, 8]. Work has been done on Mg substituted NiCuZn ferrite by many research people to study its structural and magnetic properties [9, 10, 11]. In present paper first attempt has done for Substituting Mg in Ni 2 Z hexaferrite. The key intention of this work was to study the structural and magnetic properties of Ni2Z by the addition of diamagnetic Mg 2+ ion. Such diamagnetic substitution in Z hexaferrite might enrich its structural as well magnetic properties. II. EXPERIMENTAL PROCEDURE In the present work 11 compounds with chemical composition Sr 3 Mg x Ni 2-x Fe 24 O 41 where x = 0, 0.2, 0.4, 0.6, 0.8, 1, 1.2, 1.4, 1.6, 1.8, 2 were prepared by solid state reaction method with AR grade oxides. All the reacting carbonate and oxides are first mixed in their appropriate proportion. The powders were mixed in agate mortar using AR grade acetone for 9 hr to achieve uniform grain size and homogeneity. The palate of this mixture is prepared by applying the pressure of 10 tones psi using hydraulic press for 5 to 7 minutes. These pallets are then heated at 900°C for about 5 hr and then cooled at room temperature. Then the temperature of furnace is set to 1250°C and kept it constant for 6 hr. The furnace is then cooled slowly at the rate of 20°C per hour up to 1000°C and then allows the furnace cooled in natural way to room temperature. These pallets are finally powdered and used for further experimental investigations. Thermal analysis of the SrCO 3 , MgO, NiO and α-Fe 2 O 3 powder mixture milled for 9 hr was carried out in air by using thermo gravimetric (TG) and differential thermal analysis (DTA) (Diamond TG/DTA, PERKIN ELMER, USA) in order to investigate the thermal decomposition behaviour, phase transitions, phase formation temperature of the Z hexaferrite in the temperature range of 25 °C to 1400 °C at the rate of 10 °C/min. The sintered samples were investigated by means of XRD Philips, Panalytical X’pert, using Cu Kα radiation to