Magnetic coupling parameters at an oxide-oxide interface from first principles: Fe2O3-FeTiO3

Nabi, Hasan Sadat; Harrison, Richard J. und Pentcheva, Rossitza (2010): Magnetic coupling parameters at an oxide-oxide interface from first principles: Fe2O3-FeTiO3. In: Physical Review B, Bd. 81, Nr. 21

Abstract

Charge mismatch at the interface between canted antiferromagnetichematite (alpha-Fe2O3) and antiferromagnetic ilmenite (FeTiO3) isaccommodated by the formation of mixed Fe2+ and Fe3+ contact layers,leading to uncompensated magnetic moments in the system. To derive themagnetic exchange interaction parameters of the end members andinterface, we map total-energy differences of collinear spinarrangements obtained from density-functional theory calculations to aHeisenberg Hamiltonian using the least-squares method. Parameters forthe end members, hematite (J(m)(3+,3+)) and ilmenite (J(m)(2+),(2+)) arein good agreement with the values obtained from inelasticneutron-scattering data. The magnetic interaction parameters betweenFe2+ and Fe3+ (J(m)(2+,3+)) in the contact layer show a strongantiferromagnetic coupling to the adjacent hematite layers and thusexplain the ferrimagnetism in the system.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Geowissenschaften > Department für Geo- und Umweltwissenschaften > Kristallographie und Materialwissenschaft
• Themengebiete: 500 Naturwissenschaften und Mathematik > 530 Physik ; 500 Naturwissenschaften und Mathematik > 540 Chemie ; 500 Naturwissenschaften und Mathematik > 550 Geowissenschaften, Geologie
• Sprache: Englisch