title: A study of interface-sustained ferromagnetism in 1/2(1-x)Ln2O3-xSrO/1/3Co3O4 nano-composite.
abstract: The binary oxide composite, consisting of rock salt-type SrO and spinel Co3O4 nano-domains, exhibits soft ferromagnetic properties at ambient temperature. This ferromagnetism is originated from interface-induction, and the magnitude of the magnetic properties can be enhanced when the spinel phase of the composite is doped by a small amount of Ln2O3 (Ln = La, Nd, for instance). In this work, we study the composites of tri-oxide, 1/2(1-x)Ln2O3-xSrO/1/3Co3O4, where 0.01 < or =1-x < or = 0.6, by focusing on three areas: (i) generation of nano-composite dominant by interfacial phase via the pyrolysis of preceramic metallo-organic gel; (ii) influence of post-pyrolysis calcination and Ln2O3 content on the phase composition of the composite; and (iii) elucidation of different magnetic responses caused by the nature of Ln2O3 dissolved in the Co3O4 phase. The Ln(3+)-doped Co3O4 oxide displays only paramagnetic behavior at room temperature, but the ferromagnetic response is attained upon its mixing with SrO in nano-scale. The SrO phase plays the role in assisting Co3O4 phase with aligning unpaired electrons through interfacial induction.
authors.affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore, BLK E5 02-02, 4 Engineering Drive 4, 117576 Singapore; Institute of Materials Research and Engineering, 3 Research Link, 117602 Singapore.
authors.forename: Siok Wei
authors.initials: SW
authors.lastname: Tay
authors.forename: Liang
authors.initials: L
authors.lastname: Hong
authors.forename: Zhaolin
authors.initials: Z
authors.lastname: Liu