Thickness dependence of the crystallization of Ba-ferrite films

Abstract

The crystallization of Ba-ferrite/sapphire(001) films of various thicknesses has been studied using synchrotron x-ray scattering, field emission scanning electron microscope, and atomic force microscope. In films thinner than 1000 Å, Ba-ferrite amorphous precursor was crystallized into perpendicular grains keeping the magnetically easy c-axis normal to the film plane during annealing to 750 °C. In films thicker than 1000 Å, however, acicular grains keeping the c-axis parallel to the film plane were grown on top of the perpendicular grains. The behavior of the saturation magnetization and the intrinsic coercivity was consistent with the thickness dependence of the crystallization. We attribute the thickness dependence of the crystallization to the substrate effect, which prefers the growth of the epitaxial, c-axis oriented perpendicular grains near the film/substrate interfacial area.

Effects of the grain boundary on the coercivity of barium ferrite BaFe12O19

“…Hexagonal barium ferrite, BaFe 12 O 19 ; has been extensively investigated because it is a promising candidate for future high-density recording media as well as having microwave-linked applications [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. The large coercivity, corrosion resistance, and high chemical stability of barium ferrite has also led to its widespread use in permanent magnets and recording materials.…”

Influence of the growth conditions on the magnetism of SrFe$_{12}$O$_{19}$ thin films and the behavior of Co / SrFe$_{12}$O$_{19}$ bilayers

“…Concomitantly, we have observed that the increase in sputtering power/thickness of the film tends to align the magnetization parallel to the sample plane. The work by Cho et al [40] had already pointed out the dependence of the magnetization with the film thickness for barium ferrite, BFO (which is isostructural with SFO) on sapphire (001). In that study, they found that at thicknesses less than 100 nm, the BFO grains grew perpendicular to the substrate surface with the c-axis out-of-plane, while at larger thicknesses elongated grains grew at the top of the columnar grains parallel to the surface substrate, their c-axis lying also parallel to the surface plane.…”

Sapphire orientation dependence of the microstructure of ZnO thin film during annealing

“…The mosaic distribution, which is usually studied by measuring the FWHM in the theta (θ )-rocking curve of Bragg reflection, represents the epitaxial quality of a thin film [10,11]. The mosaic distribution of the as-deposited ZnO films with a 2400-Å-thick was composed of the sharp and the broad components with about 0.02 • and 1.86 • FWHMs, respectively (data not shown).…”