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Flux Synthesis, Modulated Crystal Structures, and Physical Properties of RE Mn 0.5 SeO ( RE = La, Ce)
Author(s) -
Peschke Simon,
Nitsche Fabian,
Johrendt Dirk
Publication year - 2015
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201400603
Subject(s) - manganese , antiferromagnetism , crystallography , crystal structure , flux method , selenide , flux (metallurgy) , materials science , band gap , single crystal , chemistry , condensed matter physics , physics , selenium , metallurgy
The selenide oxides RE Mn 0.5 SeO ( RE = La, Ce) were synthesized by heating RE 2 O 3 , RE , Mn, and Se in a NaI/KI flux at 800 °C, and their modulated crystal structures determined by X‐ray single crystal and powder diffraction { P 1 1 2/ n ( αβ ½)0 s , Z = 2, LaMn 0.5 SeO: a = 405.7(1), b = 405.7(1), c = 915.2(1) pm, γ = 90°, q = [1/10, –1/10, ½]; CeMn 0.5 SeO: a = 402.0(1), b = 401.8(1), c = 910.7(1) pm, γ = 90.000(4)°, q = [0.0789(2), –0.0783(2), ½]}. The structures are related to the ZrCuSiAs‐type structure with ordered vacancies at the manganese sites. The resulting modulations of the checkerboard pattern in the [Mn 0.5 Se] layers can be approximated by 10 a × 10 b × 2 c and 51 a × 51 b × 2 c supercells in LaMn 0.5 SeO and CeMn 0.5 SeO, respectively. Both compounds are insulators. The optical bandgap of LaMn 0.5 SeO was determined to 2.13 eV from the Kubelka‐Munk function. Magnetic measurements indicate antiferromagnetic ordering of the Mn 2+ moments with Néel points well above room temperature, as known from related manganese compounds.