title: Size-dependent passivation shell and magnetic properties in antiferromagnetic/ferrimagnetic core/shell MnO nanoparticles.
abstract: The magnetic properties of bimagnetic core/shell nanoparticles consisting of an antiferromagnetic MnO core and a ferrimagnetic passivation shell have been investigated. It is found that the phase of the passivation shell (gamma-Mn(2)O(3) or Mn(3)O(4)) depends on the size of the nanoparticles. Structural and magnetic characterizations concur that while the smallest nanoparticles have a predominantly gamma-Mn(2)O(3) shell, larger ones have increasing amounts of Mn(3)O(4). A considerable enhancement of the Néel temperature, T(N), and the magnetic anisotropy of the MnO core for decreasing core sizes has been observed. The size reduction also leads to other phenomena such as persistent magnetic moment in MnO up to high temperatures and an unusual temperature behavior of the magnetic domains.
authors.affiliation: Centre d'Investigació en Nanociència i Nanotecnologia (ICN-CSIC), Campus Universitat Autònoma de Barcelona, E-08193 Bellaterra, Spain.
authors.forename: Alberto
authors.initials: A
authors.lastname: López-Ortega
authors.forename: Dina
authors.initials: D
authors.lastname: Tobia
authors.forename: Elin
authors.initials: E
authors.lastname: Winkler
authors.forename: Igor V
authors.initials: IV
authors.lastname: Golosovsky
authors.forename: German
authors.initials: G
authors.lastname: Salazar-Alvarez
authors.forename: Sònia
authors.initials: S
authors.lastname: Estradé
authors.forename: Marta
authors.initials: M
authors.lastname: Estrader
authors.forename: Jordi
authors.initials: J
authors.lastname: Sort
authors.forename: Miguel Angel
authors.initials: MA
authors.lastname: González
authors.forename: Santiago
authors.initials: S
authors.lastname: Suriñach
authors.forename: Jordi
authors.initials: J
authors.lastname: Arbiol
authors.forename: Francesca
authors.initials: F
authors.lastname: Peiró
authors.forename: Roberto D
authors.initials: RD
authors.lastname: Zysler
authors.forename: Maria Dolors
authors.initials: MD
authors.lastname: Baró
authors.forename: Josep
authors.initials: J
authors.lastname: Nogués