Effect of Gd doping on Structural, Morphological and Magnetic Properties of Mn-Zn Soft Ferrites Nanoparticles


 Co-precipitation technique was adopted to synthesize gadolinium doped manganese-zinc ferrite nano particles with varying concentration 0, 0.1, 0.2 and 0.3. XRD patterns authenticated the ferrite innovate in the as-prepared samples. The lattice parameter, crystallite size, lattice strain and x-ray density has been calculated. The crystallite size is comes bent on be around 5 nm. The FTIR spectra reveal that every one the functional groups are present within the material. SEM images are accustomed to indicate the morphological characteristics of the as-prepared samples. Magnetic properties show the decrease in saturation magnetization from 37.57emu/g to 30.15emu/g with reference to increase in gadolinium doping from 0.1 to 0.3.


INTRODUCTION
Magnetic nanoparticles have attracted increasing interest in recent years in academic still as in technical fronts [1][2][3][4][5][6]. The magnetic properties of nanomaterial were reported to be modified than those of bulk materials. This is due to their large surface to volume ratio as compared to bulk material. Especially nano-magnetic particles have useful properties like spin canting, surface anisotropy, super-paramagnetic [7] etc. due to this, nano magnetic particles have remarkable electrical and magnetic properties and have wide selection of practical applications in information storage system, ferro fluid, magneto caloric refrigeration and magnetic diagnostics [8][9][10]. Particularly, Gd doped Mn-Zn ferrite are technologically important because of high pyro magnetic coefficient (∂M/∂T) H and includes a low curie temperature [11]. The doping of Gd 3+ ions in Mn-Zn ferrite improves the thermo-magnetic properties of material which might be useful for developing low Curie temperature ferro fluid. Several physical and chemical methods like ball milling, co-precipitation, sol-gel, hydrothermal, citrate precursor, modified oxidation, sono chemical reaction method etc. are reported within the literature [12][13][14][15][16] for the synthesis of nano magnetic particles, however the Gd ion doped Mn-Zn ferrite nanoparticles have not yet been prepared by these methods [17].
In the present investigation, nanoparticles of Mn 0.5 Zn 0.5 Gd x Fe 2-x O 4 (x=0, 0.1, 0.2 and 0.3) were prepared using chemical co-precipitation method and also the structural and magnetic properties are studied.

Characterization of Nanoparticles
The synthesized samples were characterized for structural properties using X-ray diffraction technique (XRD Rigaku Miniflex 600). FTIR spectra were recorded by using a Perkin Elmer IR spectrometer. SEM studies were performed on a ZEISS ULTRA PLUS scanning electron microscope. The magnetic properties of the as-prepared samples were studied using VSM (Lake Shore Cryotronics 7400-S).

RESULTS and DISCUSSION:
3.1 X-ray Diffractometer X-ray diffraction of as synthesized Mn 0.5 Zn 0.5 Gd x Fe 2-x O 4 (x= 0, 0.1,0.2 and 0.3) nano particle powder samples has been performed for the structural characteristics namely crystallite size, lattice parameter, crystallite phase, lattice strain and X-ray density of as prepared. The lattice parameters were calculated using the interplaner distance,'d' values and the respective (hkl) parameters. X-ray diffraction patterns of undoped and Gadolinium doped Mn-Zn ferrites with their tentative indexing are shown in Fig. 1. These pattern exhibits all the major peaks related to spinel structure without any impurity. XRD spectrum indi where, D XRD is the mean dimension of the crystallites, k is Scherrer's constant taken to be 0.9, is the x-ray wavelength (=1.5406 A°), and  is the Bragg's diffraction angle. The lattice parameter of as-prepared samples was calculated by considering cubic crystal structure, from the plane (311) main peak of spinel structure using the Bragg's equation: = ℎ ℎ 2 their tentative indexing are shown in Fig. 1. These pattern exhibits all the major peaks related to spinel structure without any impurity. XRD spectrum indicates that (311) is a prominent peak. From the full width at half maxima (FWHM) of peaks, the mean size of the crystals was estimated by using Scherrer's equation given below: is the mean dimension of the crystallites, k is Scherrer's constant taken to be 0.9, =1.5406 A°),  is the broadening of the peak width of half maximum, is the Bragg's diffraction angle. prepared samples was calculated by considering cubic crystal structure, from the plane (311) main peak of spinel structure using the Bragg's equation: their tentative indexing are shown in Fig. 1. These pattern exhibits all the major peaks related to cates that (311) is a prominent peak.
From the full width at half maxima (FWHM) of peaks, the mean size of the crystals was is the mean dimension of the crystallites, k is Scherrer's constant taken to be 0.9,  is the broadening of the peak width of half maximum, prepared samples was calculated by considering cubic crystal structure, from the plane (311) main peak of spinel structure using the Bragg's equation: where d hkl is the interplaner distance, "a" is lattice parameter, and 'h', 'k', 'l' are plane indices. The X-ray density  x is determined using the equation  = where Z = 8 (the number of atoms in cubic structure), N weight and V is volume of the cubic unit cell: a The average crystallite size, lattice parameter, strain, x been calculated using XRD data are given in Table 1.
From the XRD data table it is clear that the crystallite size is decreasing with the doping of gadolinium. The lattice parameter is increasing with doping of gadolinium; it might be due to the difference between the ionic radii of host and doping element. The X with the doping of gadolinium, it indicates that with the doping of Gd, the electron density of the sample increased.  is determined using the equation [18]: where Z = 8 (the number of atoms in cubic structure), N A is Avogadro number, M is molecular weight and V is volume of the cubic unit cell: a 3 The average crystallite size, lattice parameter, strain, x-ray density and interplaner spacing have been calculated using XRD data are given in Table 1.
table it is clear that the crystallite size is decreasing with the doping of gadolinium. The lattice parameter is increasing with doping of gadolinium; it might be due to the difference between the ionic radii of host and doping element. The X-ray density with the doping of gadolinium, it indicates that with the doping of Gd, the electron density of the

FTIR Spectrometry
The FTIR spectra of these samples were recorded over the range of 500 in figure 3. Characteristic absorption peaks are clearly observed at around 2920, 2850, 1730, 1560, 1380, 1217 and 610 cm -1 . A broad absorption band appearing at around 3420 cm spectra is the characteristic of absorbed water (O with the increase in gadolinium doping. In the figure we can show demobilize the peak observed at 1730 Peaks at 2900 cm -1 and 2850 cm stretching. The absorption peaks at around 1380 cm The absorption peaks at around 610

Scanning Electron Microscope
The FTIR spectra of these samples were recorded over the range of 500-4000 cm in figure 3. Characteristic absorption peaks are clearly observed at around 2920, 2850, 1730, . A broad absorption band appearing at around 3420 cm spectra is the characteristic of absorbed water (O-H stretching) which get slightly disappeared with the increase in gadolinium doping. In the figure we can show that he peak observed at 1730 cm -1 corresponds to aldehyde carbonyl (HC=O) group. cm -1 are due to C-H stretching and at 1560 stretching. The absorption peaks at around 1380 cm -1 and 1217 cm -1 are due to C The absorption peaks at around 610 cm -1 are for C-H bending. . A broad absorption band appearing at around 3420 cm -1 in FTIR which get slightly disappeared that the gadolinium nds to aldehyde carbonyl (HC=O) group.
cm -1 is for C=C are due to C-O stretching.

EDAX
From EDAX Studies, the traces of impurities and other elements are not identified. The observed composition ratios are consistent with expected composition ratio. This indicates that the expected stoichiometric under preparation is well maintained in the samples prepared using the co-precipitation technique.

3.4
Hysteresis Measurements Magnetic measurements were carried out of the as-prepared samples at room temperature by using vibrating sample magnetometer (VSM). The Saturation magnetization (M S ), Remanent magnetization (M r ) and coercivity (H C ) were evaluated from these measurements and given in the Table 2. Fig. 5 shows the magnetic characteristics of Mn 0.5 Zn 0.5 Gd x Fe 2-x O 4 nano ferrites samples which indicate that the magnetization first increase with the gadolinium doping and further increase in doping reduces the magnetization. This decrease in Ms with rare earth doping is due to lower magnetic ordering from the localized 4f electrons of rare earth ions from which the magnetic moments originates. So Gd 3+ substitution can be considered as a non-magnetic ion substitution in octahedral B-site. So this reduces the exchange interaction between A and B sites which results in decrease of magnetization [11,19]. It shows the ferromagnetic nature of the as prepared material.

Conclusion
Undoped and gadolinium doped Mn-Zn nano particles have been synthesized using coprecipitation method. The as-prepared nano magnetic particles were characterized for their structural, morphological and magnetic properties. In comparison to undoped ferrite nano particles, the crystallite size decreases with gadolinium doping. The surface morphology of these fine particles shows the presence of ultra fine particles when doped with gadolinium. The saturation magnetization increases while we dope the material with gadolinium also the prepared magnetic materials are ferromagnetic in nature.