Structural, magnetic and magneto-optical properties of SrFe12-xAlxO19 hexaferrite thin films prepared by laser ablation deposition

Pulse laser ablation deposition is used to produce thin films of SrFe12-xAl xO19 hexaferrites, with x in the interval 0 less than or equal to x less th an or equal to 4. The structural, magnetic, optical and magneto-optical pro perties of the films are investigated using XRD, AFM, MFM, VSM, transmissio n photometry and spectroscopic Faraday polarimetry. The films exhibit smoot h optical surface and strong perpendicular anisotropy due to the almost com plete texture with the c-axis normal to the film plane. The values of the f ilm lattice constant, c, anisotropy field, H-A, and magnetic anisotropy, K, are found to be very close to those of the corresponding, bulk material. A bsorption, Faraday rotation and ellipticity spectra of SrFe12-xAlxO19 hexaf errite films are determined over the spectral range 300-2000 nm and analyse d in terms of the microscopic dielectric tensor theory. Six paramagnetic li nes and two diamagnetic lines are identified and assigned to specific elect ron transitions. Furthermore, the fractional magnitudes of prominent extrem e of the Faraday rotation spectra are examined as functions of Al3+ concent ration to obtain an insight into the mechanism by which Fe3+ cations contri bute to the MO spectra of M-type hexaferrites. (C) 2000 Elsevier Science S. A. All rights reserved.