title: Nonstoichiometric spinel ferrites obtained from alpha-NaFeO2 via molten media reactions.
abstract: Different solid/liquid "exchange" reactions involving divalent cations, protons, or ammonium ions have been performed at low/moderate temperatures (between 80 and 500 degrees C) on alpha-NaFeO2 dipped in molten salts (or acid) media. Several ferrites have been obtained which are nonstoichiometric with partially inverse spinel structures. When sodium is replaced by divalent cations (Mg2+, Co2+, Ni2+, and Zn2+), the obtained ferrites are hyperstoichiometric (cation/oxygen ratio higher than 3/4) whereas proton or ammonium reactions result in hypostoichiometric materials (cation/oxygen lower than 3/4). All these ferrites present a platelet-like morphology and show ferrimagnetic, soft magnet behavior.
authors.affiliation: Dpto. Química Inorgánica, Fac. CC. Químicas, Universidad Complutense, 28040-Madrid, Spain. emoran@ quim.ucm.es
authors.forename: Emilio
authors.initials: E
authors.lastname: Morán
authors.forename: Ma Carmen
authors.initials: MC
authors.lastname: Blesa
authors.forename: M-Eloisa
authors.initials: ME
authors.lastname: Medina
authors.forename: Jesús D
authors.initials: JD
authors.lastname: Tornero
authors.forename: Nieves
authors.initials: N
authors.lastname: Menéndez
authors.forename: Ulises
authors.initials: U
authors.lastname: Amador