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Effect of Gd doping and O deficiency on the Curie temperature of EuO.

Jutong N, Eckern U, Mairoser T, Schwingenschlögl U - Sci Rep (2015)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Institut für Physik, Universität Augsburg, 86135 Augsburg, Germany.

ABSTRACT
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.

No MeSH data available.


Exchange interaction and corresponding TC as a function of the Gd concentration for the cubic phase ((a1), (b1)), and the tetragonal phase ((a2), (b2)).
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f3: Exchange interaction and corresponding TC as a function of the Gd concentration for the cubic phase ((a1), (b1)), and the tetragonal phase ((a2), (b2)).

Mentions: In order to clarify the effect of Gd doping for both the cubic and tetragonal phases we determine the density of states (DOS) projected on the Eu 4f, 5d, Gd 4f, 5d, and O 2p orbitals, see Fig. 2. The dependences of the different exchange terms and of TC on the dopant concentration are addressed in Fig. 3. We first discuss the results for the pristine structures (0% doping), which are very similar for the cubic and tetragonal phases. For the majority spin channel we distinguish three regions: the conduction band (dominated by Eu 5d states), upper valence band (dominated by localized Eu 4f states, with some hybridization with O 2p and Eu 5d), and lower valence band (dominated by O 2p states, with significant hybridization with Eu 4f and 5d). The spin minority channel shows a similar structure but without the Eu 4f contributions.


Effect of Gd doping and O deficiency on the Curie temperature of EuO.

Jutong N, Eckern U, Mairoser T, Schwingenschlögl U - Sci Rep (2015)

Exchange interaction and corresponding TC as a function of the Gd concentration for the cubic phase ((a1), (b1)), and the tetragonal phase ((a2), (b2)).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4306962&req=5

f3: Exchange interaction and corresponding TC as a function of the Gd concentration for the cubic phase ((a1), (b1)), and the tetragonal phase ((a2), (b2)).
Mentions: In order to clarify the effect of Gd doping for both the cubic and tetragonal phases we determine the density of states (DOS) projected on the Eu 4f, 5d, Gd 4f, 5d, and O 2p orbitals, see Fig. 2. The dependences of the different exchange terms and of TC on the dopant concentration are addressed in Fig. 3. We first discuss the results for the pristine structures (0% doping), which are very similar for the cubic and tetragonal phases. For the majority spin channel we distinguish three regions: the conduction band (dominated by Eu 5d states), upper valence band (dominated by localized Eu 4f states, with some hybridization with O 2p and Eu 5d), and lower valence band (dominated by O 2p states, with significant hybridization with Eu 4f and 5d). The spin minority channel shows a similar structure but without the Eu 4f contributions.

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Institut für Physik, Universität Augsburg, 86135 Augsburg, Germany.

ABSTRACT
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.

No MeSH data available.