Evidence for Conical Magnetic Structure in M‐Type BaFe$_{12}$O$_{19}$ Hexaferrite: A Combined Single‐Crystal X‐ray Magnetic Circular Dichroism and Neutron Diffraction Study

The magnetic ground state of BaFe$_{12}$O$_{19}$ (BFO) is investigated using X-ray absorption spectra (XAS), X-ray magnetic circular dichroism (XMCD), and neutron diffraction studies at 1.2 and 1.5 K, respectively. The XMCD measurements on single-crystals of BFO in grazing-incidence geometry reveal canting of the spins away from the c-axis of the hexagonal unit cell. Single-crystal neutron diffraction studies reveal magnetic satellite peaks along the 00l reciprocal lattice row around the forbidden l = 2n ± 1 positions confirming the conical-type magnetic structure in the ground state of BFO. The observation of the conical magnetic structure of BFO opens the possibility of type-II multiferroicity in undoped BFO