Structural, microstructural and magnetic properties of (La_1−xCa_x)MnO₃nanoparticles

Abstract

The crystal and magnetic structures of 10 and 20 nm sized (La1-xCax)MnO3 (x = 0.37, 0.50, 0.75) have been investigated between 5 and 300 K by means of Rietveld refinement of neutron powder diffraction data, coupled with transmission electron microscope observation and magnetization measurements. TEM observation reveals that nanoparticles are strongly affected by strain fields, probably originating from surface pressure. Irrespective of the composition, charge and orbital orderings are suppressed and Fz and Cy spin orderings coexist at low temperature; Cy and Fz orderings likely occur within the strained regions of the nanoparticles and in the matrix respectively. Moreover Gz and Az orderings are sometimes observed, and are likely to be taking place at the border of the strained regions.

Designing new ferrite/manganite nanocomposites

“…It should be underlined that the saturation magnetization values (table 2) of both samples are lower with respect the bulk LCMO (≈ 97 A m 2 kg -1 ), in agreement with previous literature [25][26][27] supposing a magnetically disordered surface as the origin of saturation magnetization reduction in nanoparticles.…”

Origin of Suppression of Charge Ordering Transition in Nanocrystalline Ln0.5Ca0.5MnO3 (Ln = La, Nd, Pr) Ceramics

“…This is consistent with earlier reports of Pnma structure for these manganites in bulk as well as nanocrystalline forms. 27,28,35,38,47 The particle sizes for nano samples were calculated from the Rietveld method, providing the input file containing the instrumental resolution function; this input file was obtained using Si standard. The crystallite sizes obtained by Rietveld analysis are ∼25.8(1), ∼26.2(2), and ∼28.1(1) nm for LCMO(C8), NCMO(C7), and PCMO(C8) samples, respectively.…”

Microstructural, Magnetic, and Optical Properties of Pr-Doped Perovskite Manganite La0.67Ca0.33MnO3 Nanoparticles Synthesized via Sol-Gel Process

“…La 1 − x Ca x MnO 3 (LCMO) manganite, as a prototypical system of perovskite manganites, has been of great interest because of its magnetic behavior and rich phase diagram [8, 9]. In the past decade, various synthesized methods such as sol-gel process [10, 11], polymeric precursor route [12], mechanical milling method [13], molten salt method [14] have been used to synthesize perovskite LCMO nanoparticles, and the effect of particle size on the structural, transport, and optical properties are also investigated [15–18]. Simultaneously, Ca-doped PrMnO 3 (Pr 1 − x Ca x MnO 3 : PCMO) also have some unusual electrical, magnetic, and optical properties, which are dependent on the Ca-doped concentration [19, 20].…”