Magnetic and dielectric properties of Fe₃BO₆ nanoplates prepared through self-combustion method

Abstract

In the present investigation, a facile synthesis method is explored involving a self-combustion of a solid precursor mixture of iron oxide Fe 2 O 3 and boric acid (H 3 BO 3 ) using camphor (C 10 H 16 O) as fuel in ambient air in order to form a single phase Fe 3 BO 6 crystallites. X-ray diffraction (XRD), Field emission electron microscopy (FESEM), magnetic, and dielectric properties of as prepared sample are studied. From XRD pattern, a single phase compound is observed with an orthorhombic crystal structure (Pnma space group), with average crystallite size of 42 nm. A reasonably uniform size distribution of the plates and self-assemblies is retained in the sample. A magnetic transition is observed in dielectric permittivity (at $445 K) and power loss (at $435 K) when plotted against temperature. A weak peak occurs near 330 K due to the charge reordering in the sample. For temperatures above the transition temperature, a sharp increase of the dielectric loss is observed which occurs due to the presence of thermally activated charge carriers. A canted antiferromagnetic Fe 3þ ordering in a Fe 3 BO 6 lattice with a localized charge surface layer is an apparent source of exhibiting a ferroelectric feature in this unique example of a centrosymmetric compound. An induced spin current over the Fe sites thus could give rise to a polarization hysteresis loop. Due to the presence of both ferromagnetic as well as polarization ordering, Fe 3 BO 6 behaves like a single phase multiferroic ceramics.

Solution Combustion Synthesis of Iron Oxyborate (Fe3BO6)

“…Iron oxyborate (Fe3BO6) has been used in ceramics (1), drugs, pigments, gas sensors, catalysts (2), electrodes and biological probes because of magnetic (3,4), dielectric (5), conductivity (6), optical (7), structural (8), electrochemical (9) and surface properties. It is a promising anode material in lithium-ion batteries with high reversible capacity (10), unremarkable toxicity and low cost and it is also used in sodium ion batteries with high activity (11).…”