title: Orbital frustration at the origin of the magnetic behavior in LiNiO2.
abstract: We report on the ESR, magnetization, and magnetic susceptibility measurements performed over a large temperature range, from 1.5 to 750 K, on high-quality stoichiometric LiNiO2. We find that this compound displays two distinct temperature regions where its magnetic behavior is anomalous. With the help of a statistical model based on the Kugel'-Khomskii Hamiltonian, we show that below T(of) approximately 400 K, an orbitally frustrated state characteristic of the triangular lattice is established. This then gives a solution to the long-standing controversial problem of the magnetic behavior in LiNiO2.
authors.affiliation: Laboratoire Matériaux et Microélectronique de Provence, Case 151, Université d'Aix-Marseille III and CNRS, 13397 Marseille Cedex 20, France.
authors.forename: F
authors.initials: F
authors.lastname: Reynaud
authors.forename: D
authors.initials: D
authors.lastname: Mertz
authors.forename: F
authors.initials: F
authors.lastname: Celestini
authors.forename: J M
authors.initials: JM
authors.lastname: Debierre
authors.forename: A M
authors.initials: AM
authors.lastname: Ghorayeb
authors.forename: P
authors.initials: P
authors.lastname: Simon
authors.forename: A
authors.initials: A
authors.lastname: Stepanov
authors.forename: J
authors.initials: J
authors.lastname: Voiron
authors.forename: C
authors.initials: C
authors.lastname: Delmas