Buckled Honeycomb Lattice Compound Sr₃CaOs₂O₉ Exhibiting Antiferromagnetism above Room Temperature

Abstract

Synthesis, crystal structure, and magnetic properties of a new 2:1 ordered triple perovskite Sr 3 CaOs 2 O 9 are reported. The compound crystallizes in a P2 1 /c space group and features a unique buckled honeycomb lattice of osmium. It exhibits longrange antiferromagnetic ordering with a high Neél temperature of 385 K as confirmed by susceptibility, heat capacity, and neutron diffraction measurements and is electrically insulating. This compound is also the first example of a 2:1-ordered osmate perovskite. Theoretical investigations indicate that Sr 3 CaOs 2 O 9 features a sizeable antiferromagnetic exchange between the puckered planes resulting in a high T N . The magnetic properties of the known compound Sr 3 CaRu 2 O 9 are elucidated in comparison. It shows antiferromagnetic order below T N ≈ 200 K.

Synthesis, Structure and Antiferromagnetic Large‐Distance Long‐Range Coupling of the Ruthenate(V) Sr3(Ag2/3Sr1/6)RuO6

“…In particular, both electron localization and delocalization effects are possible by interplay of onsite Coulomb interaction (U) and bandwidth (W), respectively. This can lead to magnetic order at surprisingly high temperatures as reported recently [5][6][7][8][9][10][11] Here, we report single-crystal growth, crystal structure and selected physical properties of the new ruthenate(V) Sr 3 (Ag 2/ 3 Sr 1/6 )RuO 6 . The compound shows a transition to a long-range antiferromagnetic order below 79 K with a prominently threedimensional character although the shortest distance between ruthenium(V) cations is 588 pm.…”

“…The RuÀ O distances of 198.08 (6) pm is typical for oxidoruthenates(V). [3,8] The bond lengths in the slightly twisted (13.6°) trigonal prism around Ag or Sr1 are 245.58 (7) pm. The Sr2 atom is in a distorted square antiprism of oxygen atoms with distances of 257.87 (7) [2×], 258.40 (6) [2×], 259.13 (7) [3×] and 277.48 (7) pm.…”

“…[3,8] The bond lengths in the slightly twisted (13.6°) trigonal prism around Ag or Sr1 are 245.58 (7) pm. The Sr2 atom is in a distorted square antiprism of oxygen atoms with distances of 257.87 (7) [2×], 258.40 (6) [2×], 259.13 (7) [3×] and 277.48 (7) pm. The bond valence sums calculated using the parameters listed by Gagne, Hawthorne et al [14] yield 4.67 for Ru, 1.19 for Ag, 2.12 for Sr1 and 2.07 for Sr2.…”

New Sr9Os5O23, Made Up of Quasi 1D and 2D Fragments of the Perovskite Structure

“…It is worth mentioning that Sr 5 Os 3 O 13 orders antiferromagnetically below T N ∼ 175 K coinciding with the complete charge order, whereas Sr 2 OsO 5 does not order magnetically down to 2 K. Sr 9 Os 5 O 23 does not show any charge ordering below its magnetic ordering temperature in contrast to Sr 5 Os 3 O 13 . It is noteworthy that some recently reported ternary and quaternary osmates possess interesting magnetic properties like high temperature (anti)­ferromagnetism. ,, These studies along with the current one highlight the importance of the osmium-based oxides as a new avenue to look for interesting structures with interesting magnetic properties.…”

“…It is noteworthy that some recently reported ternary and quaternary osmates possess interesting magnetic properties like high temperature (anti)ferromagnetism. 11,12,38 These studies along with the current one highlight the importance of the osmium-based oxides as a new avenue to look for interesting structures with interesting magnetic properties.…”