1. Structural and Elastic properties of In3+ substituted Cu-Zn ferrite nanoparticles prepared by wet chemical method
Ketan A Ganure1*, Laxman A Dhale1, Vinod Tukarm1, Ram H Kadam2, Kishan S Lohar1
1Dept. of Chemistry, Sri krishna Mahavidyalaya Gunjoti, Omerga, Osmanabad , Maharashtra, India.
2Dept. of Physics, Sri krishna Mahavidyalaya Gunjoti, Omerga, Osmanabad , Maharashtra, India.
Abstract
The Nano crystalline ferrites with chemical formula Cu0.5Zn0.5Fe2-xInxO4. (x=0.00, 0.02, 0.04, 0.06, 0.08 and 0.10) prepared by wet chemical method. The thermo gravimetric analysis (TG) was carried out to know the annealing temperature. The single phase cubic spinel structure was confirmed by using x-ray diffraction patterns for all the samples. The structural parameter such as lattice constant, porosity, x-ray density, hopping length etc., measured with composition x by using XRD. The particle size of all the samples calculated from XRD data was found in the range of 10 nm to 20 nm. IR spectra analysis clearly shows two absorption bands in the range of 200 to 800 cm-1, high frequency tetrahedral bands ‘υ1’ are found near 625 cm-1and octahedral bands ‘υ2’ are found near 400 cm-1. The elastic properties such as rigidity modulus, young modulus and bulk modulus measured.
Keywords: Nano ferrites, wet chemical method, cation distribution and elastic properties.
INTRODUCTION
Spinel ferrites are commercially important materials because of their excellent electrical and magnetic properties. These properties make iron-containing oxides suitable for numerous device applications, including magnetic materials, sensors, magneto-optic sensors, anode materials for batteries, sensors in space applications, lasers, phosphorescent sources, microwave and electrochemical devices, black and brown pigments. Since these magneto-particles have also been shown to be non-cytotoxic, they would be suitable for biotechnological applications.
The present work deals with the synthesis of Cu0.5Zn0.5Fe2-xInxO4, nano ferrites of different composition. The crystal structure and cation distribution of Cu- Zn Ferrite nano crystals can be controlled by adjusting the synthesis route. The synthesized nano ferrites have been characterized by TG/DTA, XRD and FT-IR.
EXPERIMENTAL
The following chemicals CuSO4.6H2O, ZnSO4.6H2O, In2(SO4)3.9H2O, and Fe2(SO)4.9H2O are used as the starting materials for the synthesis of Cu0.5Zn0.5Fe2-xInxO4 nanocrystalline ferrites with composition x=0.00, 0.02, 0.04, 0.06, 0.08 and 0.10 using wet chemical method. In order to obtain desired composition, stoichiometric amount of corresponding sulphates were dissolved in distilled water and NaOH (2M) solution was added till pH becomes ~11 with constant stirring at temperature 60°C in oxygen atmosphere. The precipitate was digested for 3 hrs at the same temperature and then it is thoroughly washed with distilled water until it became free from sodium ions and dried in oven.
The elemental analysis has been carried out for all the samples of ferrites by energy dispersive spectroscopy (EDS).The decomposition pattern of the corresponding metal hydroxide was examined by thermogravimetry (TG) and differential thermal analysis (DTA) in an oxygen atmosphere at a heating rate of 10 °C/min on TG and DTA instrument. The x-ray patterns of the synthesized samples were recorded at room temperature using CuKα radiation on Jeol–JDX-8030, x-ray diffractometer. The x-ray diffraction data recorded in the range of 2θ with scanning rate 2 °/min. The Fourier Transform Infrared Spectroscopy (FT-IR) measurement was carried out in the range of 200 – 800 cm-1 on Perkin Elmer infrared spectrometer.
RESULT AND DISCUSSION
The elemental analysis of all samples Cu0.5Zn0.5Fe2-xInxO4. (x=0.00, 0.02, 0.04, 0.06, 0.08 and 0.10) were carried out by EDS method. The theoretical and observed percentages of samples are near about a very small error in wet (W) and annealed wet (AW) samples prepared by wet chemical method.
The typical curve of TG/DTA of sample x = 0.04 is shown in Fig. 1. From analysis of sample, it is observed that loss crystalline water in the range 120 – 140 °C; at temperature range 420 – 470°C, the metal hydroxides are converted into corresponding metal oxides and these metal oxides are at temperature range 550 – 650 °C undergo solid state reaction with formation of nanocrystalline ferrites.
The x-ray diffraction (XRD) patterns of annealed Cu0.5Zn0.5Fe2-xInxO4(x=0.00, 0.02, 0.04, 0.06, 0.08 and 0.10) are shown in Fig. 2. The values of lattice constant “a” were determined with an accuracy ± 0.002Å. x-ray density and porosity are tabulated in Table 1. It is observed that lattice parameter decreases with In3+ substitution, and due to the larger ionic radii of In3+as compared to that of Fe3+ ions. Similarly increase in lattice parameter due to In3+ substitution is observed in other ferrite system .
On the basis of experimental values of lattice constant, the values of tetrahedral and octahedral bond length (dAX and dBX), tetrahedral shared and unshared octahedral edges (dAXE, dBXE and dBXEu are calculated, and represented in Fig. 3(a) and 3(b) respectively as a function of In+3 content x. Figure. 3(a) shown that tetrahedral bond length and octahedral bond length (dAX and dBX) is decreases as In+3 ion concentration increases. Figure. 3(b) shown that tetrahedral edge (dAXE) and unshared octahedral edge (dBXEu) and shared octahedral edge (dBXE) decreases with increase in the concentration of In+3 ion, this due to larger ionic radius of In+3 ion as compared to Fe+3 ion.
Figure 3: (a) Effect of In+3 substitution x on tetrahedral (dAX) and octahedral (dBX) bond length of Cu0.5Zn0.5Fe2xInxO4(x=0.0, 0.02, 0.04, 0.06, 0.08 and 0.1).
Figure 3: (b) Effect of In+3substitution x on tetrahedral dAXE, shared dBXE and unshared octahedral dBXEU edge, of Cu0.5Zn0.5Fe2-xInxO4 (x=0.0, 0.02, 0.04, 0.06, 0.08 and 0.1).
The FT-IR spectral analysis of samples shown in Fig. 4, there are three absorption bands in the range of 200 –800 cm-1. Absorption band assigned as υ1and υ2in the range of 610 to 625 cm-1 and 360 to 400 cm-1 respectively. The band υ1 and υ2 bands are attributed to the intrinsic vibrations of tetrahedral and octahedral respectively. These bands are mainly dependent on the Fe+3 – O-2 distance for (A) and [B] site. The values of band frequencies are tabulated in Table 2.
Table 2: Composition, Band frequencies (υ1 and υ2), bond lengths (RA and RB) and Poisson’sRatio (σ) of Cu0.5Zn0.5Fe2-xInxO4 (x=0.0, 0.02, 0.04, 0.06, 0.08 and 0.1).
Compositions
υ1 cm- 1
υ2 cm-1
RA(Å)
RB(Å) σ
Cu0.5Zn0.5Fe2O4
610.76
376.12
0.571
0.685
0.2760
Cu0.5Zn0.5Fe1.98In0.02O4
623.01
392.52
0.605
0.686
0.2740
Cu0.5Zn0.5Fe1.96In0.04O4
618.23
363.58
0.638
0.688
0.2720
Cu0.5Zn0.5Fe1.94In0.06O4
625.19
370.33
0.672
0.689
0.2689
Cu0.5Zn0.5Fe1.92In0.08O4
364.55
0.705
0.690
0.2659
Cu0.5Zn0.5Fe1.90In0.10O4
626.45
397.45
0.709
0.692
0.2605
Figure 4: Infrared spectra of Cu0.5Zn0.5Fe2xInxO4(x=0.0, 0.02, 0.04, 0.06, 0.08 and 0.1).
In present system bonds between Fe+3 and In+3 atoms are residual bond and due to this stiffness constant decreases with increase in In+3 content. These two stiffness constants are further used to calculate the various elastic constants such as; Young’s modulus (Y), Bulk modulus (B) and Rigidity modulus (R) and is shown in Fig. 5 and 6 respectively.
Table 1: Composition, secondary phase, lattice constant (‘a’ observed and theoretical), x-ray density (dx), bulk density (dB), Percentage Porosity (P), Particle size (DXRD), Hopping lengths (LA and LB) Cu0.5Zn0.5Fe2-xInxO4 (x=0.00, 0.02, 0.04, 0.06, 0.08 and 0.10).
Compositions
a(obs.) (Å)
a(Theo.) (Å)
Dx (Å)
dB (g/cm3)
P (%)
DXRD (nm)
LA (Å)
LB (Å)
Cu0.5Zn0.5Fe2O4
8.447
8.481
5.292
3.558
37.058
16.026
3.657
2.986
Cu0.5Zn0.5Fe1.98In0.02O4
8.378
8.478
5.451
3.423
37.206
14.132
3.627
2.962
Cu0.5Zn0.5Fe1.96In0.04O4
8.331
8.423
5.570
3.159
43.283
13.481
3.607
2.945
Cu0.5Zn0.5Fe1.94In0.06O4
8.309
8.368
5.642
3.303
41.454
12.273
3.598
2.937
Cu0.5Zn0.5Fe1.92In0.08O4
8.301
5.686
2.864
49.619
11.077
3.594
2.935
Cu0.5Zn0.5Fe1.90In0.10O4
8.285
8.242
5.791
2.843
49.828
10.383
3.587
2.929
Figure 5: Variation of stiffness constants (C11) and (C12) with composition x.
Figure 6: Variation of elastic moduli with composition x.
CONCLUSION
Cu0.5Zn0.5Fe2-xInxO4 nanocrystaline ferrite prepared by wet chemical method. An elemental analysis shows that there is negligible error in theoretical, wet and annealed wet samples.
Average crystalline size was found in nano range of nm. An infrared spectral study suggested that weakening of inter atomic bonding on In+3 substituted Cu – Zn ferrite support by decrease in force constant, while Poisson’s ratio almost remains constant.
The stiffness constant and elastic moduli values can be determined by the infrared spectral analysis and it decreases with In+3 substitution.
Figure 1: The typical curve of TG/DTA of sample
x= 0.04.
Figure 2: x-ray diffraction of Cu0.5Zn0.5Fe2xInxO4(x=0.00, 0.02, 0.04, 0.06, 0.08 and 0.10)
ACKNOWLEDGMENTS
The one of authors Ketan A Ganure and Dr. K. S. Lohar are thankful to U.G.C. New Delhi, for providing financial support according to grant F.No /2013.