Antiferromagnetically spin polarized oxygen observed in magneto-electric TbMn2O5

TL;DR

This study directly measures antiferromagnetic spin polarization at oxygen sites in TbMn2O5, providing experimental support for theories on magnetoelectric coupling involving oxygen spin polarization.

Contribution

It presents the first direct measurement of oxygen spin polarization in TbMn2O5 and links it to the Mn3+ ion positions, advancing understanding of magnetoelectric mechanisms.

Findings

Oxygen spin polarization observed via resonant soft x-ray scattering.

Resonance linked to hybridization with Mn3+ ions.

Mn3+ ion positions influence oxygen spin polarization.

Abstract

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 wavevector. 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 Mn3+ ions. Furthermore we have discovered that the position of the Mn3+ ion directly influences the oxygen spin polarization.