Orbital control of noncollinear magnetic order in nickel oxide heterostructures

Phys Rev Lett. 2013 Sep 6;111(10):106804. doi: 10.1103/PhysRevLett.111.106804. Epub 2013 Sep 5.


We have used resonant x-ray diffraction to develop a detailed description of antiferromagnetic ordering in epitaxial superlattices based on two-unit-cell thick layers of the strongly correlated metal LaNiO3. We also report reference experiments on thin films of PrNiO3 and NdNiO3. The resulting data indicate a spiral state whose polarization plane can be controlled by adjusting the Ni d-orbital occupation via two independent mechanisms: epitaxial strain and spatial confinement of the valence electrons. The data are discussed in light of recent theoretical predictions.