Investigation of the growth of garnet films by liquid phase epitaxy
Liquid phase expitaxy was investigated to determine its applicability to fabricating magnetic rare earth garnet films for spacecraft data recording systems. Two mixed garnet systems were investigated in detail: (1) Gd-Y and (2) Eu-Yb-Y. All films were deposited on Gd3Ga5012 substrates. The uniaxial anisotropy of the Gd-Y garnets is primarily stress-induced. These garnets are characterized by high-domain wall mobility, low coercivity and modest anisotropy. Characteristic length was found to be relatively sensitive to temperature. The Eu-Yb-Y garnets exhibit acceptable mobilities, good temperature stability and reasonable quality factors. The uniaxial anisotropy of these garnets is primarily growth-induced. The system is well suited for compositional "tailoring" to optimize specific desirable properties. Liquid phase epitaxy can be used to deposit Gd3Ga5012 spacing layers on magnetic garnet films and this arrangement possesses certain advantages over more conventional magnetic filmspacing layer combinations. However, it cannot be used if the magnetic film is to be ion implanted.
The temperature dependence of the anisotropy field and coercivity in epitaxial films of mixed rare‐earth iron garnets
The temperature dependence of the anisotropy field Hk and the domain‐wall coercivity Hc have been measured for three different epitaxial films of mixed rare‐earth iron garnets with the nominal compositions Er2Eu1Ga0.7Fe4.3O12, Y1Eu1.85Yb0.15Al1.1Fe3.9O12, and Eu1.7Er1.3Al0.7Ga0.8Fe3.5O12. Each of these garnets supports bubble domains. The anisotropy field was measured using an optical magnetometer, and analytical expressions are developed which relate the optical magnetometer parameters to the anisotropy field. These measurements show that the anisotropy field decreases with increasing temperature at about −1%/°C at 20°C for all three samples. The coercivity, again measured by an optical technique, was also found to decrease with increasing temperature. The coefficient ranged from −1.3%/°C to −3.0%/°C at 20°C depending on the sample. The largest total change in Hc for one of the samples was a factor of 310 over the temperature range −106°C to +80°C. The temperature variation of the saturation magnetizatio...
Paul, Jules, and Marie Tannery (With a Note on Grégoire Wyrouboff)
T Marie Tannery, whose life and work ended on 27 January I945, but it is impossible to speak of her without speaking of her husband, to whom the whole of her mature life was devoted though she survived him forty-one years. An elaborate biography of Paul Tannery appeared in Osir's 4 (1938); there is no need of repeating here all the details, it will suffice to recall the main facts for the reader's guidance.