Publications::
Heidler, J.; Piamonteze, C.; Chopdekar,R.V.; Uribe-Laverde, M.A.; Alberca, A.; Buzzi, M.; Uldry, A.; Delley, B.; Bernhard, C.; Nolting, F.
Manipulating magnetism in La0:7Sr0:3MnO3 via piezostrain
Journal: Phys. Rev. B 91 (2015), 024406
We present a detailed study of the ferromagnetic/ferroelectric heterostructure
La0:7Sr0:3MnO3/[Pb(Mg1=3Nb2=3)O3]0:68 -[PbTiO3]0:32 (011), where reversible electrical switching
induces a 10 K shift of the magnetic Curie temperature TC. Two distinct polarization congurations
can be set in the ferroelectric substrate and are stable at remanence; reciprocal space
maps highlight the accompanying lattice parameter changes which impose a biaxial strain on
the manganite thin lm. The magnetic response to the strain changes is probed by temperature
dependent Mn L3;2 x-ray magnetic circular dichroism and resistance measurements. X-ray natural
linear dichroism spectra for both strain states probe the valence charge anisotropy: The existing
population imbalance between out of plane and in-plane oriented orbitals increases further with
tensile strain, favouring orbital occupation in the surface plane. Multiplet and density functional
theory calculations support the emerging picture that an increase in tensile in-plane strain leads
to an increased energy dierence between the two eg orbitals and a larger Mn-O-bond length.
Increasing the electron-lattice coupling and reducing the eg electron itinerancy that leads to
ferromagnetism due to double exchange coupling, results ultimately in lower TC values.