Magnetic structure and properties of the honeycomb antiferromagnet [Na(OH)]Mn(NCS)

• Published in: Physical chemistry chemical physics : PCCP 2024-06, Vol.26 (22), p.15844-15849
• Main Authors: Geers, Madeleine, Gill, Thomas B, Burnett, Andrew D, Bassey, Euan N, Fabelo, Oscar, Cañadillas-Delgado, Laura, Cliffe, Matthew J
• Format: Article
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/d4cp01265h

We report the magnetic structure and properties of a thiocyanate-based honeycomb magnet [Na(OH 2 ) 3 ]Mn(NCS) 3 which crystallises in the unusual low-symmetry trigonal space group P 3&cmb.macr;. Magnetic measurements on powder samples show this material is an antiferromagnet (ordering temperature T N,mag = 18.1(6) K) and can be described by nearest neighbour antiferromagnetic interactions J = −11.07(4) K. A method for growing neutron-diffraction sized single crystals (>10 mm 3 ) is demonstrated. Low temperature neutron single crystal diffraction shows that the compound adopts the collinear antiferromagnetic structure with T N,neut = 18.94(7) K, magnetic space group P 3&cmb.macr;′. Low temperature second-harmonic generation (SHG) measurements provide no evidence of breaking of the centre of symmetry. [Na(OH 2 ) 3 ]Mn(NCS) 3 is a trigonal molecular framework. A combination of neutron diffraction, magnetometry and low-temperature second-harmonic generation show it orders into the classical honeycomb antiferromagnet ground state.