EuO Thin Films Research Articles

Magnetic Properties of EuO Thin Films Doped with Transition Metal

EuO films were doped with Co, Ag, or Au and their characteristics studied. These results were then compared with EuO films containing either additional Fe or Eu. It was found that films containing a transition metal had a higher Curie temperature than those containing additional Eu, and the magnetization of films doped with Ag or Fe had similar temperature dependence (a nearly linear decrease at T3/2). Two Curie temperatures were observed in films doped with Co or Au, indicating two magnetic phases.

The diffusion of oxygen vacancies and electrical properties of EuO thin films doped with Eu

The electrical properties of EuO thin films doped with Eu prepared by oxidation of evaporated Eu metal films were studied. The influence of technological conditions on the concentration of oxygen vacancies in Eu-rich EuO thin films was considered. A model of oxygen vacancy diffusion was used to explain the dependence of electrical resistivity on diffusion time.

Magnetoresistance and photomagnetoresistance of EuO thin films near the Curie temperature

Magneto and photomagnetoresistance of two different EuO thin films are studied near the Curie temperature. The results enable us to deduce the variation of carriers concentration near the Curie temperature which explains that the maximum of resistivity occurs at higher temperature than Curie temperature. The results indicate that the activation energy of carriers concentration does not depend on long range order only.

Magnetic order effect on optical absorption and photoconductivity in EuO thin films

The comparison of optical absorption with photoconductivity with left and right circularly polarized light versus temperature, shows similar behaviours. The transition responsible for photoconductivity has been assigned to a 4 f-5 d transition. Arguments are proposed to explain the relation between absorption which occurs between the 4 f correlated levels and the 5 d levels more delocalized and photoconductivity which has the same optical cause but whose electron is delocalized in a conduction band.

Transport properties of Europium oxide thin films

Conductance, photoconductivity and free lifetime of charge carriers in EuO thin films have been measured between 4°K and 400°K. The anomalous behaviour of conductance below 70°K in a lightly unintentionally doped sample is due to the simultaneous variation of mobility and concentration of the charge carriers.

Magnetic circular dichroism of EuO films

We report on the magnetic circular dichroism (MCD) spectra of EuO thin films having a [200] preferential growth, for <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6\deg &lt; T &lt; 300\deg</tex> K under low or high magnetic fields according to the spectral range investigated. A tentative interpretation of the temperature dependence of the spectra is proposed. Zero field spectra have been obtained after previous magnetization of the sample below T <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</inf> ; this provides a new method to determine T <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</inf> in zero field.