Effect of La substitution on the structural and chemical properties of Barium hexaferrite via Mossbauer spectroscopy

Abstract

M-type Barium hexaferrite is a famous hard magnetic material with a hexagonal crystal structure. La substituted Barium hexaferrite, Ba(1-x)La(x)Fe12O19, (where, x = 0.25 and 0.30) were synthesized using ball milling followed by sintering at 1300 °C for 5 hours. X-ray diffraction patterns reveal the formation of a single-phase magnetoplumbite structure of barium hexaferrite, which belongs to the P63/mmc space group. Mossbauer spectroscopic studies were carried out to study the magnetic phase, the effect of La doping on the valency of the Fe atom, and charge distribution in the prepared samples. Mossbauer spectra is fitted using 5 sextets, shows there is 5 sublattices present in the system. From the fitting of Mossbauer spectrum, it is observed that, there is no formation of Fe2+ ion even if the doping levels are as high as 30%, as it is expected that Fe3+ ion changes its valance to maintain the charge neutrality. However, there is an increase in s-electron density for number of sites with doping. Quadrupole splitting values shows spherical charge distribution for all the sublattices except 2b, due to asymmetric nature of bipyramidal site. Slightly varied magnetic hyperfine splitting values are observed for 12 k and 4f1 sites shows the effect of La substitution.

Microstructural, morphological and magnetic behaviour of Al3+ replaced BaFe11.5Co0.5O19 hexaferrites synthesized via sol-gel auto combustion route

“…M-type hexaferrites are a well-known class of magnetic materials with a broad range of applications due to their unique magnetic and structural properties. Because of their large magneto-crystalline anisotropy, they have exceptional magnetic properties, such as high saturation magnetization and high coercivity [1][2][3]. These are also well-suited for use in severe environments due to their low dielectric loss, exceptional chemical stability, and resistance to corrosion [4][5][6].…”

Structural, Magnetic, and Magneto-Optical Properties of Thin Films of BaM Hexaferrite Grown by Laser Molecular Beam Epitaxy

“…Intensive studies of films and nanostructures based on hexaferrites continue to the present. Recent papers on this topic, in particular, present the results of studying strontium hexaferrite (SrFe 12 O 19 ) films obtained by pulsed laser deposition [ 32 ], the effect of La substitution on the structural and chemical properties of barium hexaferrite [ 33 ], the magnetic properties of nanostructured BaFe 12 O 19 synthesized by sol–gel spontaneous combustion [ 34 ], mechanical regulation magnetic properties of uniaxial anisotropic thin films of hexaferrite [ 35 ] etc. The main objectives of presented article were fabricating epitaxial thin (with thickness h = 50–500 nm) films of hexaferrite BaM (BaFe 12 O 19 ) grown by laser molecular beam epitaxy on α-Al 2 O 3 (0001) substrates, studying the chemical composition, surface morphology, crystal structure, static and dynamic magnetic properties, and magneto-optical spectroscopy.…”