Structural and Magnetic Properties of a New Type of Ordered Oxygen-Deficient Perovskite, KMnVO4

• Published in: Chemistry of materials Vol. 19; no. 23; pp. 5563 - 5569
• Main Authors: Yahia, H. Ben, Gaudin, E, Lee, C, Whangbo, M.-H, Darriet, J
• Format: Journal Article
• Language: English
• Published: American Chemical Society 13-11-2007
• Subjects: Chemical Sciences; Material chemistry
• ISSN: 0897-4756; 1520-5002
• DOI: 10.1021/cm070452b

A new ternary vanadate KMnVO4 was prepared by a solid-state reaction and was shown to be a new type of ordered oxygen-deficient perovskite ABO3   -   δ with δ = 1/3. Its formula can be rewritten as (K2,Mn)[Mn,V2]O8□1. An ordered distribution of potassium and manganese atoms in the A site and of vanadium and manganese atoms in the B site is observed. The manganese atoms are in distorted octahedral and tetrahedral sites, whereas all of the vanadium atoms form VO4 3- tetrahedra. This oxide contains four different types of high-spin Mn2+ ions in equal number. Magnetic susceptibility and specific heat measurements as well as spin dimer analysis show that substantial antiferromagnetic spin-exchange interactions occur primarily among three of the four different types of Mn2+ ions, and the fourth Mn2+ ion remains paramagnetic down to 2 K.