Soft chemical control of the crystal and magnetic structure of a layered mixed valent manganite oxide sulfide

Abstract

Oxidative deintercalation of copper ions from the sulfide layers of the layered mixed-valent manganite oxide sulfide Sr2MnO2Cu1.5S2 results in control of the copper-vacancy modulated superstructure and the ordered arrangement of magnetic moments carried by the manganese ions. This soft chemistry enables control of the structures and properties of these complex materials which complement mixed-valent perovskite and perovskite-related transition metal oxides.

Synthesis, Structure, and Compositional Tuning of the Layered Oxide Tellurides Sr2MnO2Cu2–xTe2 and Sr2CoO2Cu2Te2

“…5 The difference in a and b in the 100 K data is 0.00211(1) Å (i.e., ∼0.05%; see Table S5 for the refined Immm model). 4)) is larger than for Sr 2 CoO 2 Cu 2 S 2 (0.00024(2)), 5 but smaller than for Ba 2 CoO 2 Cu 2 S 2 (0.002127 (7)). 5 This suggests that the orbital contribution to the magnetic moment might not be the sole contributor to the size of the orthorhombic distortion: the identity of the chalcogenide ion may be important.…”

“…5,33 The magnetic moment of Sr 2 CoO 2 Cu 2 Te 2 also has a significant orbital contribution, so it is likely that the orthorhombic distortion of Sr 2 CoO 2 Cu 2 Te 2 arises from a similar magnetostriction. The orthorhombic distortion of Sr 2 CoO 2 Cu 2 Te 2 (parametrized by (b/a)-1:0.000509(4)) is larger than for Sr 2 CoO 2 Cu 2 S 2 (0.00024(2)), 5 but smaller than for Ba 2 CoO 2 Cu 2 S 2 (0.002127 (7)). 5 This suggests that the orbital contribution to the magnetic moment might not be the sole contributor to the size of the orthorhombic distortion: the identity of the chalcogenide ion may be important.…”

“…While the copper-site vacancies in Sr 2 MnO 2 Cu 1.5 S 2 order on cooling, 4 no analogous long-range structural ordering is observed in the selenide analogue Sr 2 MnO 2 Cu 1.5 Se 2 , 4 and this may be a consequence of lower Cu mobility in the selenide layer than in the sulfide layer in these compounds. Consistent with this, it was also found that, while copper could be topotactically deintercalated from Sr 2 MnO 2 Cu 1.5 S 2 at ambient temperatures to produce Sr 2 MnO 2 Cu 1.33 S 2 , with a complex incommensurately modulated structure with copper/vacancy ordering at room temperature, 7 Sr 2 MnO 2 Cu 1.5 Se 2 8 and Sr 2 MnO 2 Ag 1.5 Se 2 9…”

“…The subambient temperature was used to minimize side reactions. 7 Powder Diffraction Measurements. Initial structural characterization was carried out by powder X-ray diffraction (PXRD) on a Bruker D8 Advance Eco instrument (Bragg−Brentano geometry, Cu Kα radiation).…”

Metal Oxysulfides: From Bulk Compounds to Nanomaterials

“…Zhu, Hor, and Otzschi also detailed different quinary oxysulfide families: (i) the Sr 2 Cu 2 MO 2 S 2 [M = Mn (Zhu and Hor, 1997a), Co (Zhu et al, 1997;Smura et al, 2011), Zn (Zhu and Hor, 1997a), Ni (Otzschi et al, 1999)] and Ba 2 Cu 2 CoO 2 S 2 (Zhu et al, 1997;Smura et al, 2011) family that displays an unusual square planar MO 2 layer and the two perovskite-based families (ii) Sr 3 Cu 2 M 2 O 5 S 2 [M = Sc (Otzschi et al, 1999), Fe (Zhu and Hor, 1997b)] and (iii) Sr 2 CuMO 3 S [M = Sc (Ogino et al, 2012), Cr (Zhu and Hor, 1997b), Fe (Zhu and Hor, 1997b), Ga (Zhu and Hor, 1997c), In (Zhu and Hor, 1997b)] with the work of Ogino on scandium. Later, Blandy transformed Sr 2 Cu 2 MnO 2 S 2 in Sr 2 Cu 1.5 MnO 2 S 2 by oxidative deintercalation of copper to obtain a mixed-valent perovskite (Blandy et al, 2015).…”