A Generalizable Multigram Synthesis and Mechanistic Investigation of YMnO₃ Nanoplates

Abstract

The reproducible gram-scale synthesis of crystalline nanoscale multiferroics is critical for the development of the next generation of commercially relevant electronic devices. Of the subset of multiferroic materials, yttrium manganese oxide (YMnO3) is highly attractive, because of its large magneto-electric coupling constants and the recent observation of giant polarization under pressure in these types of rare earth manganites. Utilizing a unique synthetic methodology that combines metal–oleate thermal degradation with the use of a molten salt protocol, we were able to reproducibly generate monodisperse distributions of morphologically distinctive yttrium manganese oxides. Specifically, using a molten NaCl flux, we were able to synthesize phase-pure, single-crystalline hexagonal YMnO3 nanoplates, measuring 441 ± 241 nm in diameter and 46 ± 6 nm in height. Moreover, these nanoplates gave rise to multiferroic behavior, which was confirmed by the observation of a ferroelectric phase from a combination of high-resolution TEM (HRTEM) and selected-area electron diffraction (SAED) analysis. Magnetic measurements are consistent with the onset of a spin glass state below 5 K. To highlight the generalizability of the synthetic method we have developed herein, as a demonstration of principle, we have also successfully used the same protocol to produce nanocubes of lanthanum aluminum oxide (LaAlO3).

Determining the Photoelectrical Behavior and Photocatalytic Activity of an h-YMnO3 New Type of Obelisk-like Perovskite in the Degradation of Malachite Green Dye

“…We analyzed the chemical composition for h-YMnO 3 using XPS. The full-spectrum scan (Figure 4A) revealed the presence of the chemical elements Y, Mn, O, and C, whose binding energies agree with those reported in the literature [17,20]. The peak associated with C is due to the carbon-based tape used to fix the sample while analyzed.…”

“…Additionally, semi-triangular structures attached to the surface of the microrods appear after calcination. Comparing the morphology obtained in this work with those reported for h-YMnO 3 [17][18][19], we found that those microstructures have not been reported for this oxide. This suggests that the formic acid reaction with the yttrium and manganese nitrates allows this morphology to form, avoiding the surfactants used.…”

“…Furthermore, the Mn 2p spectrum was deconvoluted, from which four Gaussian curves were obtained and identified as Mn 3+ and Mn 4+ (dotted lines in figures 4C and D). The curves centered at 641.6 and 653.3 eV (Mn 3+ ) are associated with the +3 manganese oxidation state, while those localized at 644 and 651.7 eV (Mn 4+ ) are associated with the +4 [17]. Similarly, the O spectrum 1s was deconvoluted, as Figure 4D shows.…”

Molten Salt Synthesis of Micro-Sized Hexagonally Shaped REMnO3 (RE = Y, Er, Tm, Yb)

“…Few different studies dealing with the preparation of YMnO 3 by molten salt synthesis have been already reported [26][27][28]. In all cases, either NaCl or the eutectic mixture of NaCl and KCl were used as the reaction medium.…”

Virtual Special Issue: Invited Papers from the 252nd ACS National Meeting in Philadelphia

“…Another theme that emerges from this collection is advances in materials for energy applications. ,, These articles discuss solar cells, supercapacitors, and hydrogen storage. This Virtual Special Issue also features new work on CO 2 capture and storage, − carbon nanotube assemblies, gas separation, and synthesis of nanomaterials for electronic devices …”