Effect of oxygen pressure on microstructure and magnetic properties of strontium hexaferrite (SrFe 12O 19) film prepared by pulsed laser deposition

Abstract

The effects of oxygen pressure during deposition on microstructure and magnetic properties of strontium hexaferrite (SrFe 12O 19) films grown on Si (100) substrate with Pt (111) underlayer by pulsed laser deposition have been investigated. X-ray diffraction pattern confirms that the films have c-axis perpendicular orientation. The c-axis dispersion (Δθ 50) increases and c-axis lattice parameter decreases with increasing oxygen pressure. The films have hexagonal shape grains with diameter of 150250 nm as determined by atomic force microscopy. The coercivities in perpendicular direction are higher than those in in-plane direction, which shows the films have perpendicular magnetic anisotropy. The saturation magnetization and anisotropy field for the film deposited in oxygen pressure of 0.13 mbar are comparable to those of the bulk strontium hexaferrite. Higher oxygen pressure leads to the films having higher coercivity and squareness. The coercivity in perpendicular and in-plane directions of the film deposited in oxygen pressure of 0.13 mbar are 2520 Oe and 870 Oe, respectively. © 2011 Elsevier B.V. All rights reserved.