Antiferromagnetically Spin Polarized Oxygen Observed in Magnetoelectric TbMn2O5

T. A. W. Beale (1) , S. B. Wilkins (1, 2) , R. D. Johnson (1) , S. R. Bland (1) , Yves Joly (3) , T. R. Forrest (4) , D. F. Mcmorrow (4) , F. Yakhou (5, 6) , D. Prabhakaran (7, 8) , A. T. Boothroyd (7) , P. D. Hatton (9)

1 Department of Physics
2 Brookhaven, Natl Lab.
3 NEEL - SIN - Surfaces, Interfaces et Nanostructures
4 London Centre for Nanotechnology
5 SIMaP - Science et Ingénierie des Matériaux et Procédés
6 ESRF - European Synchrotron Radiation Facility
7 Department of Physics, Clarendon Laboratory
8 Clarendon Laboratory [Oxford]
9 Department of Physics

We report the direct measurement of antiferromagnetic spin polarization at the oxygen sites in the multiferroic TbMn2O5, through resonant soft x-ray magnetic scattering. This supports recent theoretical models suggesting that the oxygen spin polarization is key to the magnetoelectric coupling mechanism. The spin polarization is observed through a resonantly enhanced diffraction signal at the oxygen K edge at the commensurate antiferromagnetic wave vector. Using the FDMNES code we have accurately reproduced the experimental data. We have established that the resonance arises through the spin polarization on the oxygen sites hybridized with the square based pyramid Mn3þ ions. Furthermore we have discovered that the position of the Mn3þ ion directly influences the oxygen spin polarization.

Mots clés: multiferroic; TbMn205; Resonant X-ray Diffraction

Domaines: Science des matériaux [cond-mat.mtrl-sci]

T. A. W. Beale, S. B. Wilkins, R. D. Johnson, S. R. Bland, Yves Joly, et al.. Antiferromagnetically Spin Polarized Oxygen Observed in Magnetoelectric TbMn2O5. Physical Review Letters, 2010, 105, pp.087203. ⟨10.1103/PhysRevLett.105.087203⟩. ⟨hal-00686547⟩