A Liquid-Precursor Synthesis of Single-Phase Magnetoelectric LaFeO<SUB>3</SUB> Nanocrystallites

Abstract

LaFeO 3 , a nontoxic and thermally stable compound, when prepared of small crystallites offers tailored magnetic and magnetoelectric properties at room temperature. In this article, we describe synthesis of a phase pure LaFeO 3 of nanocrystallites with a bonded carbon surface layer from a liquid precursor at moderate temperature in air. The results demonstrate that, upon sonication and microwave heating, the metal ions La 3+ and Fe 3+ in an inorganic-organic precursor cluster and grow into LaFeO 3 crystallites in a specific shape of nanoplates, typically 40-150 nm in width and 15-25 nm in thickness, at moderate temperature ∼700 C in ambient air. The stable phase LaFeO 3 stands in an orthorhombic crystal structure (Pnma space group), on sintering to obtain useful ferroelectric properties in a dense pellet. At room temperature, a sintered pellet (at 950 C for 4 h) measures a wide ferroelectric hysteresis loop, showing a polarization of 2.05 C/cm 2 , remnant polarization of 0.78 C/cm 2 , and coercivity 7.65 kV/cm for an applied electric field up to 18 kV/cm (at 500 Hz). These values are compatible to those known in important granular multiferroics such as BiFeO 3 and composites.

Dynamics of Surface Spins in Small Core–Shell Magnets of Li0.35Zn0.30Fe2.35O4 Bonds over a Carbon Surface and Tailored Magnetic Properties

“…On a GO network bonds to O 2– from a ferrite lattice it expands over a parent graphene value of d 002 = 0.3410 nm, , what is it is also shown in the characteristic Raman bands briefed in the next section. A similar d 002 = 0.3920 nm is also shown in GO bonds to LaFeO 3 . A still larger d 002 = 0.420 nm emerges in sp 3 -C bonds on Fe 3 O 4 .…”

“…Magnified HRTEM images in Figure 5b,c display how different strains in the layers 1 and 2 cause different (002) separations d 002 = 0.3750 and 0.3770 nm in a GO-like network, respectively. On a GO network bonds to O 2− from a ferrite lattice it expands over a parent graphene value of d 002 = 0.3410 nm, 36,37 what is it is also shown in the characteristic Raman bands briefed in the next section. A similar d 002 = 0.3920 nm is also shown in GO bonds to LaFeO 3 .…”

“…A similar d 002 = 0.3920 nm is also shown in GO bonds to LaFeO 3 . 37 A still larger d 002 = 0.420 nm emerges in sp 3 -C bonds on Fe 3 O 4 . 17 Evidently, it is the interface interbonds the two phases in this example determines how it can bond over sp 2 and sp 3 -C on an oxide surface and in turn tune the associated properties.…”

Synthesis and surface modified hard magnetic properties in Co0.5Pt0.5 nanocrystallites from a rheological liquid precursor

“…The first part of the endotherm at 451 1C arises primarily as a bare PVP decomposes with other polymeric lingers, while a more stable surface PVP layer bonded on the NCs crumbles later in a reasonably weaker endothermic peak displaced at 475 1C. A bonded carbon yield, which often graphitizes and deposits in molecular layers on a metal surface [19,21] upon a carbon linger relieves, burns-up in an exothermic peak as seen at 600 1C in Fig. 3A.…”

Magnetic, dielectric, and ferroelectric properties in Bi3+-substituted Li0.35Zn0.3Fe2.35-xBixO4 (x = 0.1) nanocrystallites

“…There are only a few naturally occurring single phase materials called multiferroics (Cr 2 O 3 and BiFeO 3 ), which exhibit a spontaneous magnetization with electric polarization. The Fe 3+ (3d 5 ) spins ordered antiferromagnetically induce a lattice distortion that creates a local electric field and thus a ferroelectric ordering arises in such orthoferrites [7]. Recently some new single phase compounds have been developed, such as Bi 3+ -substituted ferrites, which offer superior electromagnetic properties with low dielectric loss (tanδ).…”