Ferromagnetic Mn 3+ Sawtooth Chains in A 2 (Mn 2 O)(SeO 3 ) 3 (A = K, Rb) Quaternary Selenites

• Published in: Inorganic chemistry Vol. 63; no. 23; p. 10471
• Main Authors: Li, Yaping, Li, Feifan, Mentré, Olivier, Minaud, Claire, Arévalo-López, Ángel M, Huang, Qingqing, Cheng, Xiedong, Cui, Rui, Lü, Minfeng
• Format: Journal Article
• Language: English
• Published: United States 10.06.2024
• Series: Inorg Chem
• Subjects: Chemical Sciences; Inorganic chemistry
• ISSN: 0020-1669; 1520-510X; 1520-510X
• DOI: 10.1021/acs.inorgchem.3c03522

Two quaternary manganese selenites, A (Mn O)(SeO ) (A = K, Rb), have been synthesized by hydrothermal reactions. They both crystallize in a complex triclinic (P-1) structure built of Jahn-Teller (JT) distorted Mn O octahedra, connected into nearly isosceles [Mn O ] triangles, themselves arranged into so-called "sawtooth (ST) chains". The K and Rb compounds show subtle variations in the orientations of the MnO planes inside the elementary triangles. The ST chains are structurally and magnetically isolated by SeO groups and alkali cations. In the ST chains, predominant ferromagnetic interactions were calculated and verified experimentally, which finally order antiferromagnetically between the chains around ≈ 22 K. The spin exchanges calculated by DFT + and fitted by Monte Carlo simulations allow for the quantification of an effective "overall" model. The specific role of the μ -O bridge on the ferromagnetic (FM) exchanges is discussed, together with spin reorientations observed in the ordered state. Magnetocrystalline anisotropy along the [110] direction stabilized by ∼50 meV per Mn by spin-orbit coupling (SOC) was found by DFT + + SOC.