Synthesis, Structural Characterization, and Physical Properties of the New Transition Metal Oxyselenide Ce₂O₂ZnSe₂

Abstract

Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. ABSTRACT: The quaternary transition metal oxyselenide Ce 2 O 2 ZnSe 2 has been shown to adopt a ZrCuSiAs-related structure with Zn 2+ cations in a new ordered arrangement within the [ZnSe 2 ] 2-layers. The color of the compound changes as a function of cell volume, which can vary by ~0.4%. under different synthetic conditions. At the highest, intermediate and lowest cell volumes the color is yellow-ochre, brown and black respectively. The volume decrease is attributed to oxidation of the Ce from +3 to +4, the extent of which can be controlled by the synthetic conditions. Ce 2 O 2 ZnSe 2 is a semiconductor at all cell volumes with experimental optical band gaps of 2.2, 1.4 and 1.3 eV for high, intermediate and low cell volume samples respectively. SQUID measurements show Ce 2 O 2 ZnSe 2 to be paramagnetic from 2-300 K with a negative Weiss temperature of θ = -10 K suggesting weak antiferromagnetic interactions.

Structure determination from powder diffraction data: past, present and future challenges

“…For example, Kerman et al have demonstrated that a simulated annealing approach to determining which modes are important can be used to deduce the true P2 1 /n symmetry of room temperature WO 3 . Evans and co‐workers have shown that this approach can also be used to determine the pattern of metal occupancies in a complex family of oxychalcogenides.…”

Crystal structure and magnetic modulation in β−Ce2O2FeSe2

“…One important family of compounds is those with general composition Ln 2 O 2 MSe 2 (Ln = La, Ce; M = Mn, Fe, Zn, Cd) [3][4][5][6][7][8][9][10][11] and closely related composition such as La 2 O 2 Cu 2−4x Cd 2x Se 2 [12]. These materials are semiconductors with band gaps varying from ∼0.3 to ∼3.3 eV [1,[3][4][5]8,10,11,[13][14][15][16].…”

“…There has been significant recent research on oxychalcogenide materials due to their important electronic and magnetic properties and the area has been recently reviewed [1][2]. One important family of compounds is those with general composition Ln2O2MSe2 (Ln = La, Ce; M = Mn, Fe, Zn, Cd) [3][4][5][6][7][8][9][10][11] and closely related composition such as La2O2Cu2-4xCd2xSe2 [12]. These materials are semiconductors with band gap varying from ~0.3 eV to ~ 3.3 eV [1, 3-5, 8, 10-11, 13-16].…”

Flux Synthesis, Crystal Structures, and Magnetism of the Series La2n+2MnSen+2O2n+2 (n = 0–2)

“…Numerous new compounds with the general formula RE 2 TSe 2 O 2 (RE = La, Ce; T = Cd, Fe, Mn, Zn) [1][2][3][4][5][6][7][8][9] have been discovered and their structures and magnetism have been studied. Among the particular families, different polymorphs may exist which makes the diversity even bigger.…”