title: Theory of high Tc ferrimagnetism in a multiorbital Mott insulator.
abstract: We propose a model for the multiorbital material Sr(2)CrOsO(6), an insulator with remarkable magnetic properties and the highest T(c) ~/= 725 K among all perovskites with a net moment. We derive a new criterion for the Mott transition (U(1)U(2))(1/2)>2.5W by using slave-rotor mean field theory, where W is the bandwidth and U(1(2)) are the effective Coulomb interactions on Cr(Os) including Hund's coupling. We show that Sr(2)CrOsO(6) is a Mott insulator, where the large Cr U(1) compensates for the small Os U(2). The spin sector is described by a frustrated antiferromagnetic Heisenberg model that naturally explains the net moment arising from canting and also the observed nonmonotonic magnetization M(T). We predict characteristic magnetic structure factor peaks that can be probed by neutron experiments.
authors.affiliation: Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: O Nganba
authors.initials: ON
authors.lastname: Meetei
authors.forename: Onur
authors.initials: O
authors.lastname: Erten
authors.forename: Mohit
authors.initials: M
authors.lastname: Randeria
authors.forename: Nandini
authors.initials: N
authors.lastname: Trivedi
authors.forename: Patrick
authors.initials: P
authors.lastname: Woodward