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Notes: Recent research has demonstrated that large amounts of hydrogen can be electrolytically incorporated in amorphous, compositionally modulated (CM) FeZr films. The first irreversible changes in the magnetic state of an electrolytically hydrogenated iron-rich amorphous alloy were observed. The hydrogen-induced changes in the magnetization were interpreted in terms of specific structural rearrangements. In this work, simultaneous measurements of the variations in the magnetization and mechanical properties of these films were measured as a function of hydrogen charging to further clarify the hydrogen-induced structure changes. The Young's moduli E and internal friction d of as-deposited, and as-hydrogenated CM Fe80Zr20 thin films were calculated from the displacements of a vibrating composite cantilever, measured using a laser heterodyne interferometer (LHI) having a displacement sensitivity of ∼0.01 A(ring). E and d were measured using the resonant frequency method. CM films with thickness 1390 A(ring) and modulation wavelength ∼10 A(ring) were deposited on glass cantilevers (5 mm long, 2 mm wide, and 150 μm thick) by sequentially sputtering (rf diode) elemental Fe and Zr targets.The samples were electrolytically hydrogenated for various times in 2 N phosphoric acid with a current density of 26.3 mA/cm2. The maximum change in magnetization of the film (from 71.5 to 551 emu/cm3) was observed after 5 min. During this time, E increased 18-fold from 535 GPa to 9.63 TPa. The unusually high Young's modulus of the as-deposited CM film is comparable to those previously observed in other CM films. The change is three times larger than the change in the E of carbon steel at the martensitic transformation, and nine times larger than the hydrogen induced increase in E of pure single crystals of iron. The d of the cantilever resonance decreased with hydrogenation, indicating that the incorporated H reduced the internal friction of the CM film. Preliminary analysis of the results indicates that the mechanical and magnetic changes can be interpreted in terms of similar atomic scale changes. Measurements on films with different CM wavelengths are in progress. © 1996 American Institute of Physics.

Notes: A systematic study of the effect of sputtering conditions, for each layer of the magneto-optical SiN 500 A(ring)/TbFeCo 200 A(ring)/SiN 200 A(ring)/Al 600 A(ring) disks, such as power and Ar gas flow rate on the noise levels (NL) and carrier-to-noise ratio (CNR) was performed for the 532 nm high density storage media in this work. The NL dropped to its minimum value of −71.3 dB as the sputtering power for the first SiN increased from 0.5 to 1.5 kW. With a further increase in sputtering power to 2.5 kW, it sharply increased to −64.5 dB. This was ascribed to the smooth and dense surface of the first layer at 1.5 kW, as was observed in the atomic forces microscopy images. The spherical, isotropic, fine grains with a diameter of about 0.2–0.7 μm at 1.5 kW were found, while the longitudinal, directional granular features with a length of 2.5 μm were seen at 2.5 kW. The highest CNR of 46.3 dB was observed at 0.6 kW with a constant sputtering Ar gas flow rate of 25 sccm for the magneto-optical layer. The sputtering conditions for other layers are as follows: 1.5 kW with sputter Ar/N2 gas flow rate of 30 sccm/11 sccm for the first and third SiN layer, and 0.6 kW with 25 sccm of Ar for the Al reflection layer. This is due to the smooth surface morphologies of the magneto-optical layer at this optimum sputtering pressure, as previously reported in similar research. To obtain a high readout signal, the phase compensation for the elliptic laser beam has been considered. © 1996 American Institute of Physics.