Ferromagnetism and increased ionicity in epitaxially grownTbMnO3films

Authors :: Diego Rubi
C. de Graaf
Ria Broer
Christophe Daumont
D. Mannix
Beatriz Noheda
Zernike Institute for Advanced Materials
Theoretical Chemistry
Source :: Physical Review. B: Condensed Matter and Materials Physics, 79(1):014416. AMER PHYSICAL SOC
Publication Year :: 2009
Publisher :: American Physical Society (APS), 2009.
Abstract: Thin films of TbMnO3 have been grown on SrTiO3 substrates. The films grow under compressive strain and are only partially clamped to the substrate. This produces remarkable changes in the magnetic properties and, unlike the bulk material, the films display ferromagnetic interactions below the ordering temperature of ~40K. X-ray photoemission measurements in the films show that the Mn-3s splitting is 0.3eV larger than that of the bulk. Ab initio embedded cluster calculations yield Mn-3s splittings that are in agreement with the experiment and reveal that the larger observed values are due to a larger ionicity of the films.<br />Comment: REVTeX, 5 two-column pages, 4 EPS figures