Investigating structural, magnetic and multiferroic properties of gadolinium substituted strontium hexaferrite (SrFe12-xGdxO19)

Abstract

An economical and citrate precursor based sol-gel technique is employed for pure phase synthesis of Gd3+ substituted M-type strontium hexaferrite (SrFe12-xGdxO19) for x = (0.25 - 1.00). The XRD patterns reflected all prominent planes related to hexagonal symmetry (P63/mmc space group). The crystallite size and induced strains is determined using Williamson-Hall plot. Lattice constants (a) and (c) shows minor increments with Gd3+ concentration. Particle distributions in SEM micrograph agree with W-H plot analysis. FTIR analysis is in consistent with X-ray intensity results. The ‘Law of Approach’ to saturation is applied to estimate parameters such as, magnetization (Ms) of order 40.91 to 57.7 emu/g and retentivity (Mr) ranging from 26.3 to 32.5 emu/g. A remarkable increase in coercivity (HC) is observed with increasing Gd3+ composition, with a value of 2500 to 6310 Gauss. Moreover, incorporation of Gd3+ in SrFe12-xGdxO19 lattice hinders electrical leakage profitably to yield remanent (Pr) and coercive polarization (Pc) of order 0.19 μC/cm2 and 17 kV/cm respectively. Thus sol-gel method proves to be useful in synthesizing nanomaterials of enhanced physical properties along with it being cost effective. Therefore, we are reporting tuning of magnetic and multiferroic properties of SrFe12O19 due to crystal strain mediated by Gd3+ doping at Fe3+ site.