Effects of high nonstoichiometry on EuO properties
作者:
O. Massenet,
Y. Capiomont,
Nguyen Van Dang,
期刊:
Journal of Applied Physics
(AIP Available online 1974)
卷期:
Volume 45,
issue 8
页码: 3593-3599
ISSN:0021-8979
年代: 1974
DOI:10.1063/1.1663822
出版商: AIP
数据来源: AIP
摘要:
Electric, magnetic, and electron paramagnetic resonance (EPR) measurements have been performed on thin EuO films prepared either by reactive evaporation of Eu at 400°C or by oxidation of a Eu metal thin film at 200–250°C. The films obtained by reactive evaporation have electrical and magnetic properties very similar to those reported for EuO single crystals of various degrees of nonstoichiometry. The films prepared by oxidation of Eu films at 200–250°C are characterized by a much higher‐valued Curie temperature (Tc≃148 K), while their resistivity is in the range 10−2−1 &OHgr; cm. The EPR signal can be attributed to Eu spins, which shows that in these films there exist fluctuations of Eu doping due to nonstoichiometry. We analyzed the high concentration of oxygen vacancies in the bound magnetic polaron (BMP) model. A high level of defects and oxygen vacancies, inhomogeneously distributed in the film, can account for both their electrical and magnetic properties.
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