Accession Number : AD0477109

Title :   THE EXCITATION OF MAGNETOACOUSTIC WAVES AT MICROWAVE FREQUENCIES.

Descriptive Note : Scientific rept. no. 1, 1 Nov 64-31 Oct 65,

Corporate Author : SPERRY RAND RESEARCH CENTER SUDBURY MA

Personal Author(s) : Damon, R. W. ; Van de Vaart, H.

Report Date : NOV 1965

Pagination or Media Count : 76

Abstract : A series of experiments are described showing parametric amplification of magnetoelastic and magnetostatic waves in single crystal YIG in the frequency range 1 - 10 GHz. Pulse echo techniques were used to observe amplified echoes in both axially- and transversely-magnetized rods and in normally-magnetized disks. Both the magnetoelastic and magnetostatic wave amplification involve a quasidegenerate process, with the pump frequency almost exactly twice the signal frequency. Magnetostatic wave amplification produces an echo with variable recall time, dependent only on the time of pumping and independent of magnetic field strength. At 1.5 K, this recall time can be as long as 50 microsec for X-band signals. In the case of magnetoelastic waves, the delay of the amplified echo is a function of applied magnetic field. A net gain exceeding 55 dB is obtained at 1.5 K for X-band signals with 10 microsec delay. At room temperature, 6 dB net gain is obtained in X band at 3 microsec delay with 250 W of pump power, and 17 dB net gain is obtained in L band with only 0.6 W of pump power. The observed echo behavior indicates that the transverse pumping process involves a pair of shear magnetoelastic waves on the same branch of the dispersion curve and occurs near the magnetoelastic crossover point. (Author)

Descriptors :   *ELECTROMAGNETIC RADIATION), *DELAY LINES), (*PARAMETRIC AMPLIFIERS, (*MICROWAVE FREQUENCY, MAGNETIC PROPERTIES, SINGLE CRYSTALS, YTTRIUM COMPOUNDS, IRON ALLOYS, GARNET, MAGNETIC FIELDS, X BAND, PUMPING(ELECTRONICS), PROPAGATION, S BAND, C BAND, L BAND, MAGNETRONS, K BAND, PIEZOELECTRIC TRANSDUCERS.

Subject Categories : Electrical and Electronic Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE