Origin of Ising magnetism in Ca3Co2O6 unveiled by orbital imaging

The one-dimensional cobaltate Ca 3 Co 2 O 6 is an intriguing material having an unconventional magnetic structure, displaying quantum tunneling phenomena in its magnetization. Using a newly developed experimental method, s -core-level non-resonant inelastic x-ray scattering ( s -NIXS), we were able to image the atomic Co 3 d orbital that is responsible for the Ising magnetism in this system. We can directly observe that corrections to the commonly accepted ideal prismatic trigonal crystal field scheme occur in Ca 3 Co 2 O 6 , and it is the complex d 2 orbital occupied by the sixth electron at the high-spin Co trig 3 + ( d 6 ) sites that generates the Ising-like behavior. The ability to directly relate the orbital occupation with the local crystal structure is essential to model the magnetic properties of this system. Ca 3 Co 2 O 6 has an unconventional magnetic structure displaying quantum tunnelling phenomena in its magnetization. Here, the authors use s -core-level non-resonant inelastic X-ray scattering to image the atomic Co 3 d orbital that is responsible for the Ising magnetism in this system.