Room temperature ferromagnetic (Zn,Co)O epitaxial films obtained by low-temperature MOCVD process

Abstract

High quality epitaxial films of Zn 1 x Co x O solid solutions were obtained by low temperature MOCVD process using water vapor up to x 0.33. Depositions were carried out at 300°C on r sapphire substrates. Films structure and composition were investigated by XRD, XPS and EDX measurements. Magnetic properties were examined using SQUID and Kerr effect measurements. All samples showed ferromagnetic behavior at room temperature. NEXAFS and PES were employed to investigate electronic structure of the films.

Phase stability and thermal expansion of ZnO solid solutions with 3d transition metal oxides synthesized at high pressure

“…The phase stability and thermal expansion of rs-Co It should be noted that earlier single-phase solid solutions with wurtzite structure enriched with cobalt up to 30 mol% were only prepared in the form of thin films [37]. Thus, at high pressures it is possible to produce wurtzite zinc oxide solid solutions that are significantly cobalt-saturated compared to conventional ceramic synthesis methods.…”

Superparamagnetic behavior of MOCVD grown ZnO:Co films

“…However it does not completely eliminate a possibility of embedding the cobalt ions in octahedral interstices of the wurtzite structure, which is implicitly supported by the slight increase in the wurtzite lattice parameter observed upon an increase of the cobalt concentration [9].…”

Electron transport and low-temperature electrical and galvanomagnetic properties of zinc oxide and indium oxide films

“…The details of the CVD technique are described elsewhere. 15,16 The films were deposited on single-crystal substrates of R-and C-sapphire, yttrium-stabilized zirconium oxide (YSZ), and MgAl 2 O 4 (MAO). Films of zinc oxide doped with aluminum and of indium oxide doped with tin (ITO) were produced by magnetron sputtering and deposited on glass substrates.…”

“…%; this is indicative of substitution of zinc by cobalt in the ZnO lattice. [16][17][18] The position of Co in the ZnO crystal lattice was also studied by analyzing the x-ray absorption edge (EXAFS). These data confirm that zinc is replaced by cobalt in the crystal lattice sites.…”