title: Magnetic structures of NaFePO4 maricite and triphylite polymorphs for sodium-ion batteries.
abstract: The magnetic structure and properties of polycrystalline NaFePO4 polymorphs, maricite and triphylite, both derived from the olivine structure type, have been investigated using magnetic susceptibility, heat capacity, and low-temperature neutron powder diffraction. These NaFePO4 polymorphs assume orthorhombic frameworks (space group No. 62, Pnma), built from FeO6 octahedral and PO4 tetrahedral units having corner-sharing and edge-sharing arrangements. Both polymorphs demonstrate antiferromagnetic ordering below 13 K for maricite and 50 K for triphylite. The magnetic structure and properties are discussed considering super- and supersuperexchange interactions in comparison to those of triphylite-LiFePO4.
authors.affiliation: Bragg Institute, B87, Australian Nuclear Science and Technology Organization, Locked Bag 2001, Kirrawee DC NSW 2232, Australia.
authors.forename: Maxim
authors.initials: M
authors.lastname: Avdeev
authors.forename: Zakiah
authors.initials: Z
authors.lastname: Mohamed
authors.forename: Chris D
authors.initials: CD
authors.lastname: Ling
authors.forename: Jiechen
authors.initials: J
authors.lastname: Lu
authors.forename: Mao
authors.initials: M
authors.lastname: Tamaru
authors.forename: Atsuo
authors.initials: A
authors.lastname: Yamada
authors.forename: Prabeer
authors.initials: P
authors.lastname: Barpanda