title: Anomalous magnetic properties of MnO nanoclusters.
abstract: In this communication, we experimentally report, for the first time, that the MnO nanoclusters with cluster diameters of 5-10 nm show a ferromagnetic behavior with a phase transition from ferromagnetic to paramagnetic phases at 27 K even though their bulk phase is antiferromagnetic. We observed large coercivities up to 9500 Oe and a large remanence of 1.72 emu/g at 2 K, which are typically observed values for ferromagnetic materials. Although it is not clear, this abnormal ferromagnetic behavior of MnO nanoclusters may arise from cluster size effects.
authors.affiliation: Department of Chemistry, College of Natural Sciences, Kyungpook National University, Taegu 702-701, South Korea. ghlee@bh.knu.ac.kr
authors.forename: Gang H
authors.initials: GH
authors.lastname: Lee
authors.forename: Seung H
authors.initials: SH
authors.lastname: Huh
authors.forename: Jin W
authors.initials: JW
authors.lastname: Jeong
authors.forename: Byeong J
authors.initials: BJ
authors.lastname: Choi
authors.forename: Seung H
authors.initials: SH
authors.lastname: Kim
authors.forename: Hyeong-C
authors.initials: HC
authors.lastname: Ri