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Seed size variation and its effects on germination and seedling growth were examined in seeds collected from a population of Senna occidantalis. Seed size varied from 0.009-0.029 g per seed. Final germination percentage depended on seed size with large seeds having highest germination percentage, but germination velocity was higher for small seeds. Seedlings from large seeds produced longer roots and shoots than those from small seeds and were able to emerge more rapidly. The seed size had a clear effect on survival with seedlings from large seeds having the highest survival.

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In this research work the substitutional effect of Mg2+ on Structural, Electrical Polarization, FTIR, SEM and magnetic properties of  Sr1-xMgx Mn2 Fe4 O11 R-type hexaferrite nanoparticles with compositions (x= 0, 0.25, 0.75,1.0) were investigated. The sol-gel auto-combustion method was adopted to synthesize the samples, and the powder was sintered at 800°C for 4 hours to achieve the stable hexagonal phase. XRD pattern showed that all the prepared samples have a single phase R-type hexagonal structure. The lattice parameter a, c, and unit cell volume V decreased with Mg substitution. The dislocation density increased with Mg substitution, while crystalline size varied with Mg doping. The Fourier transform infrared spectroscopy (FTIR) spectra further verified the single hexagonal phase of the produced samples. The saturation and remanent polarization increased with Mg substitution in the polarization versus electric field loops. The P-E loops also indicate the lossy behavior decreased with Mg substitution. By substituting Mg+2, the saturation magnetization, retentivity, and coercivity increased initially, then decreased. VSM measurements reveal ferrimagnetic and paramagnetic nature for all the samples.

A series of divalent Zn substituted T-type hexagonal ferrite material having the composition (x= 0.0, 0.02, 0.06, 0.1) was synthesized by using the sol-gel auto combustion method. Structural, morphological, optical, and electrical properties of T-type hexagonal ferrite were explored by using an X-ray diffractometer, scanning electron microscopy, Fourier transform infrared spectroscopy and Precision multiferroic II. The X-ray diffraction (XRD) patterns showed the single hexagonal phase ferrites for all the samples. With the substitution of the ions, the change in the values of lattice constants ‘a’, ‘c’ and unit cell volume was observed. The Debye Scherrer formula was used to calculate the crystallite size which was determined to be varied in the range of 26.3nm to 28.3nm. FTIR spectra also indicated that the present synthesized material had single-phase hexagonal structure. SEM micrographs revealed the agglomeration of small grains. The average grain size was found to be 0.331um which might be suitable for microwave absorption applications. The Polarization verse Electric field (P-E) loops unveiled the increase in saturation and remnant polarization. The P-E loops also exhibited the lossy behavior after substitution and the increase in lossy behavior with substitution results in an increase in conductivity of the material.

In present work, an investigation was carried out about the various important properties of Yb 3+ substituted Potassium based ?-hexaferrite KFe 11-x Yb x O 17 (x= 0.0, 0.02, 0.06, 0.1). The Sol-gel auto combustion technique was used to synthesize all the samples. The X-ray diffraction (XRD) patterns confirmed the single hexagonal phase for all prepared samples. The Scanning Electron Microscopy (SEM) confirmed the agglomeration of small particles into big grains. The DC electrical resistivity, measured in the voltage range of (-200V) to (200V), was observed to vary with Yb 3+ contents. The Polarization versus electric field loops revealed the lossy behaviour of pure and substitute samples which indicated the resistive nature of the samples. The saturation and remanence polarization first decreased and then increased with Yb 3+ substitution due to ferric ions distribution between octahedral sites and resistive nature of the samples, respectively. The samples exhibited peculiar magnetic behaviour with the substitution of Yb 3+ ions. The saturation magnetization was increased up to concentration x = 0.06 and then decreased with further substitution of Yb 3+ contents. The coercivity values varied in the range of 141.43 to 279.26 Oe for all the samples which confirmed the soft magnetic nature of present synthesized material. The real part (µ’) and imaginary part (µ’’) of permeability exhibited the high values at low frequencies and these values decreased with the increase of frequency. The prepared samples were supposed to be used as core material of transformer and in high frequency applications due to high resistivity value and low eddy current losses.

A series of single-phase R-type hexagonal ferrites with the composition Sr1-xMgxFe4Sn2O11 (x = 0.0, 0.1, 0.2, 0.3) were manufactured using the auto-combustion sol-gel method sintered at 800 °C. The objective of this work was to study the effect of Mg additives on the structural, magnetic, and permeability properties of the synthesised material. The X-ray diffraction patterns revealed that all prepared samples have hexagonal structures. The scanning electron micrographs revealed the platelet-like structure of the grains, which would help enhance the magnetic permeability of the materials. Magnetic parameters were investigated in the range of applied field ±12.5 kOe. The hysteresis loops revealed the paramagnetic nature of all the synthesised samples. With the substitution of Mg contents, the maximum magnetization increased from 1.05 to 2.62 (emu/g) and the remanence from 0.02-0.09 (emu/g), while the coercivity also increased. The magnetic permeability was determined over the frequency range of 20 Hz to 20 MHz. The magnetic permeability of the synthesized hexagonal ferrites is enhanced due to the presence of grains having a platelet-like structure. Furthermore, the particle size calculated using Langevin equations varied in the range of 4.7 to 6.5 nm. The calculated magnetic permeability properties make this synthesised ferrite material useful for super-high-frequency devices.