Structural and magnetic phase transition observed in the YCrO3+γ compound

Low-Temperature Oxygen Storage of CrIV–CrV Mixed-Valence YCr1–xPxO4−δ Driven by Local Condensation around Oxygen-Deficient Orthochromite

“…Figure a shows the normalized X-ray adsorption near-edge structure (XANES) spectra of YCr 0.5 P 0.5 O 4 together with three references (Cr 2 O 3 , CrO 2 , and YCrO 4 ). Pristine YCr 0.5 P 0.5 O 4 reveals similar features to those of YCrO 4 (Cr 5+ ) in the XANES region, giving rise to the large pre-edge (approximately 5981 eV) peak due to the quadrupolar 1s → 3d transitions arising from the hybridization of the 3d levels of Cr in the presence of surrounding oxygen ligands. , This pre-edge feature is characteristic of tetrahedrally coordinated Cr atoms, , and so the octahedrally coordinated Cr 2 O 3 (corundum type) and CrO 2 (rutile type) do not show such a strong pre-edge peak. Heating at 700 °C lowers the intensity of the pre-edge peak slightly, disclosing that the local coordination environments around Cr atoms are modified by oxygen deficiency at elevated temperatures.…”

A comprehensive review on the ferroelectric orthochromates: Synthesis, property, and application

“…In the true crystallographic cell of this structure, there has four distorted perovskite units. Fabian et al prepared YCrO 3+γ (γ = 0 and 1) compounds by the co-precipitation technique and performed studies with X-ray absorption near edge structure spectra and in situ XRPD [191]. The study indicates that (i) The onset of the crystallization process of the YCrO 4 phase (tetragonal, I41/amd space group) begins at ∼ 325 • C. (ii) At higher temperatures (680 ≤ T ≤ 720 • C), the phase of YCrO 3 (orthorhombic, Pbnm space group) gradually forms.…”

“…The Cr 5+ and Cr 3+ oxidation states depend on the preparation temperature. The temperature-dependent magnetic susceptibilities indicate that the zircon-like YCrO 4 phase undergoes a ferromagnetic phase transition at 9 K, and YCrO 3 displays an AFM transition at ∼ 120 K [191]. Poly-crystalline samples of YCrO 3 were prepared, and Mall et al measured temperature dependence of XRPD from 300 to 900 K [192].…”

Modeling of the oxygen defect formation in YCrO3

“…The significance of studying these materials lies in their potential use as polyfunctional catalysts for neutralizing diesel exhaust emissions, offering several advantages over traditional catalysts, namely: low cost, resistance to inhibitors, and high thermal stability. The main interest in rare‐earth metal chromites with the general formula RCrO (where R=Y or a trivalent rare‐earth ion) is currently linked to their multiferroic properties, with strong correlation between structural, electrical, and magnetic properties [20–35]. Although there have been various publications exploring the relationship between the electronic structure of complex oxides and their catalytic properties [36–39], there have been a lack of studies on oxygen mobility within the crystal lattice.…”