Effect of Gd doping and O deficiency on the Curie temperature of EuO
نویسندگان
چکیده
The effect of Gd doping and O deficiency on the electronic structure, exchange interaction, and Curie temperature of EuO in the cubic and tetragonal phases is studied by means of density functional theory. For both defects, the Curie temperature is found to exhibit a distinct maximum as a function of the defect concentration. The existence of optimal defect concentrations is explained by the interplay of the on-site, RKKY, and superexchange contributions to the magnetism.
منابع مشابه
Is there an intrinsic limit to the charge-carrier-induced increase of the Curie temperature of EuO?
Rare earth doping is the key strategy to increase the Curie temperature (T(C)) of the ferromagnetic semiconductor EuO. The interplay between doping and charge carrier density (n), and the limit of the T(C) increase, however, are yet to be understood. We report measurements of n and T(C) of Gd-doped EuO over a wide range of doping levels. The results show a direct correlation between n and T(C),...
متن کاملStudy of Pure and Gadolinium Doped Single Crystals of Europium Monoxide by Nuclear Magnetic Resonance
We performed an Eu and Eu NMR study of EuO and Gd doped EuO using a home-made spectrometer designed to measure signals with fast spin-spin relaxation times. We determined and described the broadening mechanisms giving rise to the structure in the lineshape of pure EuO. The complete description of the lineshape of pure EuO allowed us to highlight the influence of doping EuO with Gd impurities on...
متن کاملخواص ساختاری، الکترونی و دینامیک شار ابررسانای Gd (Ba2-x) Cu3O7+δ
The Gd(Ba2-xPrx)Cu3O single phase polycrystalline samples with 0.00 ≤ x ≤ 1.00 were investigated for structural, electronic and flux dynamic properties. An unusual hump on the resistivity vs. temperature curve of the samples has been observed for particular values of Pr doping. We have found that the Ba atom substitution at the rare earth site could lead to superconductivity in some parts of ...
متن کاملA magnetic polaron model for the enhanced Curie temperature of EuO(1-x).
The investigation of a series of oxygen-deficient EuO thin films provided strong evidence that the doped electrons form magnetic polarons with the nearby Eu2+ 4f spins; this is responsible for the enhanced Curie temperature observed near 140 K. Unlike in the previous magnetic polaron models proposed for the metal-to-insulator transition in EuO, the exchange coupling J between the doped electron...
متن کاملPHYSICAL PROPERTIES OF EuO VERSUS ELECTRONIC CONCENTRATIONS
Homogeneous single crystals of EuO, Eu rich EuO and Gd doped EuO have been obtained and characterized by X-ray, microprobe analysis;Mossbauer, infrared spectroscopy and resistivity measurements versus temperature. Photoconductivity, Hall effect, optical and magnetic measurements are reported. They are interpreted within a simple model taking into account Coulomb, kinetic and exchange energies a...
متن کامل