Punya Talagala

Room temperature ferromagnetism in spin-coated anatase- and rutile-Ti0.95Fe0.05O2 films

Thin films of Ti1?xFexO2?(x = 0 and 0.05) have been prepared on sapphire substrates by the spin-on technique starting from metal?organic precursors. When heat treated in air at 550 and 700??C respectively, these films present pure anatase and rutile structures as shown both by x-ray diffraction and Raman spectroscopy. Optical absorption indicates a high degree of transparency in the visible region. Such films show a very small magnetic moment at 300?K. However, when the anatase and the rutile films are annealed in a vacuum of 1 ? 10?5?Torr at 500 and 600??C respectively, the magnetic moment, at 300?K, is strongly enhanced, reaching 0.46??B/Fe for the anatase sample and 0.48??B/Fe for the rutile one. The ferromagnetic Curie temperature of these samples is above 350?K. When the ferromagnetic rutile sample is reheated in air, the magnetic moment reduces strongly. The data seem to indicate that oxygen defects created as a result of vacuum annealing may be responsible for the observed ferromagnetism in our samples.Thin films of Ti1-xFexO2 (x=0 and 0.05) have been prepared on sapphire substrates by spin-on technique starting from metal organic precursors. When heat treated in air at 550 and 700 °C respectively, these films present pure anatase and rutile structures as shown both by X-ray diffraction and Raman spectroscopy. Optical absorption indicate a high degree of transparency in the visible region. Such films show a very small magnetic moment at 300 K. However, when the anatase and the rutile films are annealed in a vacuum of 1x10-5 Torr at 500 °C and 600 °C respectively, the magnetic moment, at 300 K, is strongly enhanced reaching 0.46 µB/Fe for the anatase sample and 0.48 µB/Fe for the rutile one. The ferromagnetic Curie temperature of these samples is above 350 K.

Comparative study of stripe magnetic domains in epitaxial Ni(111) and Co(0001) films

The evolution of stripe magnetic domain structures observed by magnetic force microscopy on epitaxial Ni(111) and Co(0001) films as a function of film thickness is successfully explained by a periodic one-dimensional model with tilted partial flux closure domains. The model predicts a sizable fraction of the magnetization not being parallel to the film’s normal, which consequentially results in an in-plane magnetization in agreement with the experimentally observed magnetization for these films.

Soft Magnetic Properties of Fe - (1 wt.%) Al Alloy Processed by Powder Metallurgy

Abstract A soft magnetic material (iron with 1 wt.% aluminum) has been developed using a powder metallurgy processing route. The addition of aluminum in iron has resulted in an alloy with significant grain growth during sintering and correspondingly superior magnetic properties characterized by a low coercivity (Hc≈0.9 Oe), a relatively high permeability (μmax ≈ 5000) and a high saturated magnetic induction (Bs ≈ 13 kG at 8 Oe) after sintering at 1482°C for 12 hours. The effects of sintering time and temperature on the magnetic properties of this alloy have also been examined.