Flux Growth and Magnetic Properties of Helimagnetic Hexagonal Ferrite Ba(Fe(1–x)Sc(x))(12)O(19) Single Crystals

[Image: see text] Fabricating large, high-crystalline-quality single-crystal samples of hexagonal ferrite Ba(Fe(1–x)Sc(x))(12)O(19) is the first important step to elucidating its helimagnetic structure and developing it for further applications. In this study, single crystals of Ba(Fe(1–x)Sc(x))(12)O(19) of various Sc concentrations x were successfully grown by the spontaneous crystallization method using Na(2)O–Fe(2)O(3) flux. We determined the optimal starting composition of reagents for Ba(Fe(1–x)Sc(x))(12)O(19) growth as a function of x. In situ monitoring of the crystal nucleus generation accelerated the success of crystal growth. The obtained crystals comprised black and lamellate structures with a size of 13 mm × 8 mm × 2 mm and a surface of {001} orientation. X-ray diffraction and elemental analysis revealed that the obtained crystals were composed of single-phase Ba(Fe(1–x)Sc(x))(12)O(19) of high crystalline quality. The lattice constants a and c increased linearly with increasing x, thereby following Vegard’s law. The temperature dependence of magnetization and the magnetization curves at 77 K of the x = 0.128 crystal exhibited behavior characteristics of helimagnetism. Neutron diffraction measurements of the x = 0.128 crystal exhibited magnetic satellite reflection peaks below 211 K, providing evidence that Ba(Fe(1–x)Sc(x))(12)O(19) behaves as a helimagnetic material.