Crystal structure, magnetic properties, and Mössbauer spectroscopy of new layered iron oxyselenide Nd₂Fe₂O₃Se₂

Abstract

The crystal structure and magnetic properties of a new layered iron oxyselenide Nd(2)Fe(2)O(3)Se(2) have been investigated through powder x-ray diffraction, magnetic susceptibility, specific heat, and (57)Fe Mössbauer spectrum measurements, and electronic structure calculations. This oxyselenide crystallizes in a tetragonal structure (space group I4/mmc) which is isostructural with La(2)Fe(2)O(3)Se(2). The lattice parameters were estimated to be a = 4.0263(1) Å and c = 18.4306(2) Å by the Rietveld analysis. Through its magnetic susceptibility, specific heat, and (57)Fe Mössbauer spectrum measurements, a long-range antiferromagnetic transition of the Fe(2+) ions was found at 88 K and the Nd(3+) ions exhibited Curie paramagnetic behavior down to 2 K. Two magnetic structure models for the Fe(2+) ions were suggested from the Mössbauer spectra.

Weak spin interactions in Mott insulating La2O2Fe2OSe2McCabe1, Stock2, Rodriguez3 et al. 2014Phys. Rev. B4527630View full textAdd to dashboardCite

“…These two models are indistinguishable from powder diffraction work and in the absence of single crystals of sufficient size and quality, this ambiguity has not been resolved. We present experimental results here that favor the 2-k model proposed by Fuwa et al [18] and hope to resolve this ambiguity.…”

“…However, recent work has revealed electron correlation effects in iron pnictides suggesting that the iron-based systems may be close to the Mott boundary, yet a strongly correlated parent compound has not been clearly identified for chalcogenide and pnictide superconductors [8,9]. Also, the spin state of the Fe 2+ in these systems is not understood with different theories suggesting S = 1 or 2 ground states [10][11][12] [18]. These two models are indistinguishable from powder diffraction work and in the absence of single crystals of sufficient size and quality, this ambiguity has not been resolved.…”

Structural and magnetic characterization of iron oxyselenidesCe2O2Fe2OSe2andMcCabe1, Wills2, Chapon3 et al. 2014Phys. Rev. B139260View full textAdd to dashboardCite

“…Although the superconductivity arises in the iron arsenide layers, the Ln 3+ cation has a significant role in both tuning the superconducting T c in the doped materials [1,4] and in defining the magnetism of the parent nonsuperconducting materials (such as the spin reorientations in NdFeAsO [5] and PrFeAsO [6]). This has led to much research into the interplay between transition metal and lanthanide magnetic sublattices in these and related mixed-anion systems [7][8][9][10][11][12][13][14][15][16][17][18][19] [23] and a collinear model [10,22]. Recent work suggests that the 2-k model is the more likely [24][25][26].…”

Magnetism in La2O3(Fe1−xMnLei1, Božin2, Llobet3 et al. 2012Phys. Rev. B

“…2,3 Recently, a family of layered TMP oxychalcogenides Ln 2 O 3 TM 2 Ch 2 (Ln = rare earth, TM = transition metal, and Ch = S, Se) and its analogues A 2 F 2 TM 2 OCh 2 (A = Sr, Ba)(2322) has received more attention. [4][5][6][7][8][9][10][11][12][13][14][15][16] 2− layers transition metal atoms are located at the distorted octahedral environment due to the different distances of TM-Ch and TM-O, whereas the TM-Ch(O) octahedrons are face sharing. This distortion lifts the degeneracy of e g and t 2g levels in a non-distorted octahedral crystal field.…”