The synthesis of new geometrically frustrated layered systems encourages experimental work and progress in building models of low-dimensional magnetism. Compounds with the structure of the francisite mineral, Cu3Bi(SeO3)2O2Cl, are quasi-two-dimensional antiferromagnets with a kagome-type lattice. With the dominant ferromagnetic interaction in the layer and a weak interlayer antiferromagnetic bond, the main non-collinear state of francisite is easily destroyed by an external magnetic field, which opens the possibility of reversible switching between states with the minimum and maximum possible magnetization. In the field of metamagnetic transition observed are multiferroelectric effects and broadband absorption of electromagnetic waves. The introduction of rare-earth ions R to the Bi position is accompanied by spin-reorientation phase transitions in Cu3R(SeO3)2O2X compounds, where X = Cl, Br.
Keywords: francisite, low-dimensional and frustrated magnetism, metamagnetism, multiferroics PACS: 60.50.-f, 75.10.Jm, 75.25.+z (all) DOI:10.3367/UFNe.2020.05.038773 Citation: Markina M M, Berdonosov P S, Dolgikh V A, Zakharov K V, Kuznetsova E S, Vasil’ev A N "Francisites as a new geometrically frustrated quasi-two-dimensional magnets" Phys. Usp., accepted
Received: 17th, March 2020, revised: 4th, May 2020, accepted: 22nd, May 2020