V. Jagadeesha Angadi

Breaking of ferrimagnetic ordering in Sc3+ doped Mn-Zn ferrites due to high energy Gamma irradiation

For the first time, we report the effect of high energy gamma irradiation induced structural and magnetic properties of nanocrystalline Mn0.5Zn0.5ScyFe2-yO4 (y = 0.01, 0.03 and 0.05) samples synthesized by solution combustion method using a mixture of fuels. All samples were exposed to a dose of 25 kGy gamma radiations originating from a 60Co source. The as prepared samples and the samples after gamma irradiation were characterized by X-ray diffraction, Fourier transform Infrared spectroscopy and vibrating sample magnetometry at RT. The XRD results reveal that all the pristine samples have shown single phase cubic structure before and after gamma irradiation. The lattice parameter increases on increasing Sc3+ content after gamma irradiation. FTIR reveals that, after gamma irradiation the absorption peaks are shifted to higher frequency. In M-H loops, we observe decrease in saturation magnetization, remnant and coercivity of the samples due to breaking of ferrimagnetic ordering, when a high energy gamma ra...

Structural and dielectric behavior of Cr3+ and Gd3+ substituted Ni-Zn nano ferrites

A series of Gd3+ doped nano crystalline Ni 0.6 Zn 0.4Cr0.5GdxFe1.5-xO4 (where x=0. 00, 0.02, 0.04, 0.06) were prepared by solution combustion method using oxalyl dehydrazide (ODH) as a fuel. The Structural and dielectric behavior of as synthesized material was characterized through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR). XRD pattern reveals that the formation of single phase with cubic spinel structure. The average crystallite size and lattice parameter were found to increase with increasing Gd3+ concentration. The FTIR spectra shows two strong absorption bands at 387 cm−1 and 564 cm−1 both represents tetrahedral and octahedral stretching bonds respectively. The dielectric properties were carried out as a function of frequency and composition with the frequency range 40Hz to 10MHz. All the samples show the collective contribution of n-type and p-type carriers. The permittivity were found to decrease with increasing of Gd3+ concentration this is due to hopping off electrons and charge transport which is typical characteristic of polar dielectrics. Complex impedance was studied to know the contribution of grains and grain boundary resistance has explained according to the Maxwell Wagener type two layer model.

Effect of Sc3+ on structural and magnetic properties of Mn-Zn nano ferrites

In the present investigation, for the first time, we report on the effect of Sc3+ on the structural and magnetic properties of Mn0.5Zn0.5ScyFe2-yO4 (y = 0.01, 0.03 and 0.05) nanoferrites synthesized by solution combustion method using the mixture of fuels. As synthesized powders were characterized for the detailed structural analysis by X-ray diffractometer (XRD), Fourier transmission infrared spectroscopy (FTIR) and room temperature magnetic properties by using vibrating sample magnetometer (VSM). The results of XRD and FTIR confirm that the formation of nano crystalline, single-phased Mn-Zn ferrite with cubic spinel structure belongs to Fd-3m space group. The room temperature magnetic studies shows that, the saturation magnetization (MS), remanence magnetization (MR) and magnetic moment (ηB), magnetic particle size (Dm) have found to increase with Sc3+ ion concentration up to x = 0.3 and then decrease. The values of αY-K and the magnetic particle size (Dm) are found to be in the range of 68-75° and 10-1...