Rectangular Films Research Articles

Integrated bandpass filters

The letter presents some new results associated with one bandpass (b.p.) filter configuration of the integrated uniform R0-C0KR0 structure consisting of two rectangular resistive films, one having per-unit-length (p.u.l.) constant series resistance R0 and the other KR0 (where K is a dimensionless constant), separated from each other by a dielectric film having p.u.l. constant shunt capacitance C0. It is shown that the output voltage in the b.p. region may be made almost constant for the load fluctuations in the wide range R0 ≤ Rt < ∞ (where Rt = load resistance) by selecting K ≤ 0.3. The range of variation of Rt producing constant output voltage in the b.p. region is found to be narrower for increasing value of K.

The determination of the frequencies of magnetostatic modes in rectangular thin films of ferrimagnetic yttrium iron garnet

The determination of the frequencies of magnetostatic modes in rectangular thin films of ferrimagnetic yttrium iron garnet

The determination of the frequencies of magnetostatic modes in rectangular thin films of ferrimagnetic yttrium iron garnet

The authors have performed calculations of the frequencies of magnetostatic modes in rectangular thin-film specimens of yttrium iron garnet. The calculations have been performed for two sets of film dimensions, one set corresponding to a film on which the authors have done microwave absorption measurements and the other set corresponding to a film on which similar experiments were done previously by Tittmann (1971, 1973). In each case the thickness of the film was 12.0 mu m, and it is possible to obtain an explanation of the experimental results entirely in terms of magnetostatic modes.

Effect of magnetic field and velocity slip on porous-walled rectangular squeeze films

This is a study of an electrically conducting flow in a squeeze film between two infinite strips where one of the strips has a porous bounding surface backed by a solid wall. The analysis is directed to study the interaction of a transverse magnetic field with the coupled flows in the squeeze film and the porous medium including the slip velocity at the porous bounding surface.

Ferromagnetic Resonance in Thin Films. I. Theory of Normal-Mode Frequencies

A theory is developed for the frequencies of the general ferromagnetic normal modes of a sample of arbitrary shape and size with both exchange and demagnetization energies included. The frequencies of the modes of rectangular and circular films are calculated by casting the linearized equation of motion of the magnetization into the form of an eigenvalue equation, which is solved by a variational method. The results explain the experiments of Dillon, Besser, Sparks et al., Freedman and Brundle, and Voltmer in detail qualitatively and typically to within \ensuremath{\sim}5-10% quantitatively for the mode spacings, with possible exceptions for the first few low-order modes in some samples, for which several contributions to the line spacings are difficult to estimate accurately. Pinning the surface spins has little effect on the frequencies and intensities of magnetostatic modes (with negligible exchange energy). The theory has implications concerning the main-resonance position in finite films, and together with experiments, further verifies Portis's modespacing theory. A simple physical explanation of the results is given, and the relation of the results for for finite films to those for infinite films is given.

Preparation of single crystal films of gallium for resistance measurements at low temperatures

A method is described for preparing rectangular single crystal films of high purity gallium, 9 cm × 1 cm × 50 μ, suitable for resistivity measurements at low temperatures.

The coercive force in permalloy thin films

Work is described on arrays of rectangular permalloy thin films which shows that the domain coercive force Hc can be expressed in the form Hc = Hc min (1 + aHkδ) where Hc min is a function of the thickness, a is constant, Hk is the anisotropy field and δ is the angular dispersion. This result may be explained on the basis of magnetization ripple.

Critical Currents in Thin Planar Films

Plane rectangular films of superconducting Sn, which are thin compared to the 0 deg K penetration depth, were prepared. The currents and current densities necessary to restore the normal state in these films were measured as a function of temperature. The critical current density was found to vary as (1 - t/sup 2/)/sup 2/3/, in agreement with theory. The measurements indicate a 0 deg K critical current density on the order of 20 MA/cm/sup 2/, also in qualitative agreement with theory. (T.F.H.)