Correlation between Mn oxidation state and magnetic behavior in Mn/ZnO multilayers prepared by sputtering

Journal Article · Wed Aug 01 04:00:00 EDT 2007 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.2764207· OSTI ID:21057475

Cespedes, E; Garcia-Lopez, J; Garcia-Hernandez, M; Andres, A de; Prieto, C ^[1]

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1. Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas, Cantoblanco, Madrid, 28049 (Spain)

Compositional, microstructural, and magnetic characterization of [ZnO(30 A )/Mn(x)]{sub n} multilayers prepared by sputtering is presented to study the observed ferromagnetism in the Mn-ZnO system. The nominal Mn layer thickness, x, is varied from 3 to 60 A , while the number of bilayers, n, is increased to maintain the total amount of Mn constant. Microstructure information was deduced from x-ray reflectivity, Mn oxidation state was determined by x-ray absorption spectroscopy, and magnetic properties were measured over a temperature range of 5-400 K. Magnetic behavior of these samples is found to be related to the Mn layer thickness (x). Multilayers with x{>=}30 A exhibit ferromagnetism with a Curie temperature above 400 K, while mostly paramagnetic behavior is obtained for x<15 A . Magnetic behavior is discussed in terms of electronic and structural parameters of samples. Mn-ZnO interface effect is related to the ferromagnetic order of the samples, but it is not a sufficient condition. The essential role of the Mn oxidation state in the magnetic behavior of this system is pointed out. It is shown a correlation between the obtained ferromagnetism and a Mn oxidation state close to 2+.

• OSTI ID: 21057475
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 3 Vol. 102; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ABSORPTION SPECTROSCOPY
CURIE POINT
DEPOSITION
FERROMAGNETIC MATERIALS
FERROMAGNETISM
MAGNETIC PROPERTIES
MANGANESE
MICROSTRUCTURE
PARAMAGNETISM
SEMICONDUCTOR MATERIALS
SPUTTERING
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0000-0013 K
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
THIN FILMS
X-RAY SPECTRA
X-RAY SPECTROSCOPY
ZINC OXIDES