Effects of monovalent cation doping on the structure, microstructure, lattice distortion and magnetic behavior of single crystalline NdMnO₃compounds

Abstract

Pure and 15 mol% Na, K-doped NdMnO3 compounds with perovskite structures are prepared by sol-gel method. Tiny single crystals are formed after sintering the compounds at 1000 °C. The effect of Na and K doping as well as the effect of sintering temperature on the formation and microstructure of NdMnO3 are studied in detail by the Rietveld refinement technique using X-ray powder diffraction data. Single phase formation and single crystalline growth are also confirmed by high resolution transmission electron microscopy (HRTEM). Bond angles and bond lengths are calculated and shown by 3D diagrams. Monovalent doping induces noticeable changes in the microstructure and yields better structural stability in these compounds. Doping results in the change of Mn-O, Nd-O and Mn-O-Mn bond lengths which in turn reduces the lattice and octahedral distortion in the system along with an increase in the tolerance factor. The magnetic properties of these compounds are also modified as a result of doping. The temperature dependent magnetization results show that the Neel temperature of antiferromagnetic NdMnO3 compound is 67.2 K and the Curie temperatures of ferromagnetic Nd0.85Na0.15MnO3 and Nd0.85K0.15MnO3 compounds are 99.1 K and 98.6 K respectively. Both 15% Na and K doping results in a similar TC in doped NdMnO3 compounds.

Synergistic Regulation Effect of Nitrate and Calcium Ions for Highly Luminescent and Robust α‐CsPbI3 Perovskite

“…And when t is closer to 1.0, the perovskite would exhibit the stronger lattice symmetry. [ 24,34–36 ] As in the present case, Pb 2+ ions (ionic radius of 119 pm) have been replaced by an equivalent amount of Ca 2+ ions (small ionic radius of 100 pm), and the tolerance factor is from 0.80 significantly increased to 0.86, which is more closer to 1.0 and thereby ensures an enhanced lattice symmetry for the obtained α‐CsPbI 3 NCs.…”

“…And when t is closer to 1.0, the perovskite would exhibit the stronger lattice symmetry. [24,[34][35][36] As in the present case, Pb 2+ ions (ionic radius of 119 pm) have been replaced by an equivalent amount of Ca 2+ ions (small ionic radius of 100 pm), and the tolerance factor is from 0.80 significantly increased to 0.86, which is more closer to 1.0 and thereby ensures an enhanced lattice symmetry for the obtained α-CsPbI 3 NCs. Next, to study the effect of Ca(NO 3 ) 2 on the optical properties of CsPbI 3 NCs, the absorption and PL spectra of CsPbI 3 NCs with different Ca(NO 3 ) 2 feeding amount were measured (Figure 4a,b).…”

Effect of sodium doping on the microstructure, lattice distortion and magnetic properties of GdMnO3 tiny single crystals

“…7 and it signies presence of distortion within a single MnO 6 octahedron. 45 The change in Mn-O-Mn and O-Mn-O bond angles due to doping should inuence the magnetic properties in the doped compound.…”

Regulating the Electron Transport Mechanism and Increasing Magnetoresistance: The Role of CuO Filler in La0.7Sr0.2Ca0.1MnO3 Grain Boundary

“…For the last 20 years, there has been a lot of theoretical and experimental research on mixed valence perovskite manganates, which have a general chemical formula of R1-xAxMnO3. The "R" represents rare-earth elements, such as La, Pr, and Nd, and the "A" represents alkaline-earth metals, such as Ca, Sr, and Ba [1]- [6].…”