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.
Characteristics of Temperature‐Stable Eu‐Based Garnet Films for Magnetic Bubble Applications
Epitaxial garnet films Y3−xEuxAlyFe5−y O12, with x=1.5–2.0 and y=0.7–1.2 and small additions of Yb, are reported: with 1–7‐μ bubbles; with bubble diameters that are relatively constant versus temperature; and in which bubble velocities greater than 1500 cm/sec have been observed. These materials show promise for bubble device applications.
Superconductivity and phonon softening. III. Relation between electron bands and phonons in Nb, Mo, and their alloys
Calculations are presented by ${\ensuremath{\chi}}_{1}(\stackrel{\ensuremath{\rightarrow}}{\mathrm{Q}})$ and ${\ensuremath{\chi}}_{2}(\stackrel{\ensuremath{\rightarrow}}{\mathrm{Q}},\ensuremath{\omega})$ for Nb, Mo, and alloys in the rigid-band model. The matrix elements are set to 1. The results for Nb agree with a previous calculation by Cooke, Davis, and Mostoller. An empirical linear relation is found between ${\ensuremath{\chi}}_{1}(\stackrel{\ensuremath{\rightarrow}}{\mathrm{Q}})$ and $\frac{d{\ensuremath{\chi}}_{2}(\stackrel{\ensuremath{\rightarrow}}{\mathrm{Q}},0)}{d\ensuremath{\omega}}$. This relation leads to a simple formula relating the superconducting coupling constant ($\ensuremath{\lambda}$) to the phonon frequencies. However, we are unable to evaluate the terms in this formula with sufficient accuracy to calculate $\ensuremath{\lambda}$.