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ABSTRACT: The growth of magnetron sputtered Co/Au and Pd/Co/Au superlattices on Au and Pd buffer layers, deposited onto glass substrates, has been monitored optically and magneto-optically in real time, using rotating analyser ellipsometry and Kerr polarimetry, at a wavelength of 633 nm. The magneto-optical traces, combined with ex situ and in situ hysteresis loops, provide a detailed and informative fingerprint of the optical and magnetic properties of the films as they evolve during growth. For Co/Au, oscillations in the polar magneto-optical effect developed during the deposition of Au overlayers on Co and these may be attributed to quantum well states. However, the hysteresis measurements show that the magnetic field required to maintain saturation magnetization throughout the experiment was larger than available in situ, introducing a degree of confusion concerning the interpretation of the data. This problem was overcome by the incorporation of Pd layers into the Co/Au structure, thereby eliminating variation in magnetic orientation during growth of the Au layers as a contributory factor to the observations.
Journal of Physics Condensed Matter 08/2005; 17(34):5313. · 2.55 Impact Factor
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ABSTRACT: Existing quadrilayer and trilayer techniques for optimizing the magneto-optical effects from magnetic materials have been applied to new generation recording media to investigate the possibility of maximizing the signal-to-noise readout performance. Various methods are reviewed and the designs they produce are compared with each other and with the working media found in the literature. In order to address a number of inadequacies, a new numerical approach to the optimization of a quadrilayer structure is used to find further solutions that are considered more suitable for the practical recording media. The effects on design and performance of medium of incidence, type of storage layer and wavelength are all considered.
Journal of Physics D Applied Physics 06/2005; 38(14):2310. · 2.54 Impact Factor
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ABSTRACT: Thin, optically semi-infinite films of amorphous TbFeCo and GdFeCo, suitable for magneto-optical recording, have been deposited by DC magnetron sputtering onto glass. Ellipsometric techniques have been used to determine the complex refractive index and complex magneto-optical parameter of the films in the wavelength range 400–900 nm, thus characterizing the materials. A review of the literature is presented and shows that the results for the TbFeCo films compare favourably with published results obtained from measurements conducted in situ, with the films protected with ZnS barrier layers. It is found that GdFeCo and TbFeCo are optically very similar, but magneto-optically the materials are quite different.
Journal of Physics Condensed Matter 02/2003; 15(9):1461. · 2.55 Impact Factor
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ABSTRACT: In situ ellipsometry and Kerr polarimetry have been used to follow the continuous evolution of the optical and magneto-optical properties of multiple layers of Co and Pd during their growth. Films were sputter deposited onto a Pd buffer layer on glass substrates up to a maximum of N = 10 bi-layer periods according to the scheme glass/Pd(10)N×(0.3Co/3Pd) (nm). Magnetic hysteresis measurements taken during the deposition consistently showed strong perpendicular anisotropy at all stages of film growth following the deposition of a single monolayer of Co. Magneto-optic signals associated with the normal-incidence polar Kerr effect indicated strong polarization of Pd atoms at both Co-Pd and Pd-Co interfaces and that the magnitude of the complex magneto-optic Voigt parameter and the magnetic moment of the Pd decrease exponentially with distance from the interface with a decay constant of 1.1 nm-1. Theoretical simulations have provided an understanding of the observations and allow the determination of the ultrathin-film values of the elements of the skew-symmetric permittivity tensor that describe the optical and magneto-optical properties for both Co and Pd. Detailed structure in the observed Kerr ellipticity shows distinct Pd-thickness-dependent oscillations with a spatial period of about 1.6 nm that are believed to be associated with quantum well levels in the growing Pd layer.
Journal of Physics Condensed Matter 01/2001; 13(4):691. · 2.55 Impact Factor
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ABSTRACT: Seven TbFeCo based magneto-optic phase enhanced quadrilayers have been designed and fabricated to improve the detection of the polar Kerr effect in order to maximize the SNR associated with the read process in a magneto-optic memory. Each system consisted of ZnS/TbFeCo/ZnS/Al/glass and was fabricated using RF and DC sputtering techniques as well as conventional thermal evaporation. The experimental performance of these structures as a function of angle of incidence is reported and compared with theoretical predictions. Results obtained with incident radiation polarized in both P and S states indicate the success of the design philosophy and the fabrication procedure.
Journal of Physics Condensed Matter 12/1998; 6(17):3273. · 2.55 Impact Factor
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ABSTRACT: The fundamental optical and magneto-optical (MO) constants of high-quality, rf magnetron sputtered, thin film DyGa have been determined throughout the optical region of the spectrum (-900 nm). These constants have been used to design trilayer structures for the enhancement of the polar Kerr effect in the wavelength range -500 nm where the optical absorption of the garnet material changes rapidly and the potential for MO enhancement increases. Trilayer structures have been fabricated and their optical and MO spectral performance compared with theoretical predictions.
Journal of Physics D Applied Physics 12/1998; 31(19):2442. · 2.54 Impact Factor
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ABSTRACT: The design philosophy and objectives for producing phase‐optimized trilayer structures for magneto‐optic enhancement of the polar Kerr effect is outlined. A number of alternative designs is presented based on glass/Co‐Pt/SiO 2 /Al. The performance of an actual device, as a function of the wavelength of the incident radiation, and of angle of incidence, for both of the principal polarization states, has been evaluated experimentally and theoretically. Results indicate excellent agreement and demonstrate the ease with which devices can be designed and fabricated.
Journal of Applied Physics 06/1994; · 2.17 Impact Factor
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ABSTRACT: A study has been made of the optical and magneto-optical properties of several Co/Pt and CoNi/Pt multilayered films that were fabricated by magnetron sputter deposition. Spectroscopic rotating analyzer ellipsometry and Kerr polarimetry were carried out to determine the fundamental optical and magneto-optical constants over the spectral range 320–860 nm. The constants determined were the complex refractive index and the first-order magneto-optic Voigt parameter. A total of seven films were examined and excellent reproducibility was observed in the measured material constants. These have been used to discuss the spectral dependence of the figure-of-merit, for each material, associated with the detection of the polar Kerr effect.
Journal of Magnetism and Magnetic Materials.
