PHONON INTERACTIONS IN CRYSTALS.
Quarterly progress rept. no. 8, 15 Feb-14 May 65,
IBM WATSON RESEARCH CENTER YORKTOWN HEIGHTS N Y
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The signal velocity of MASER amplified 16.45 Gcsec ultrasonics was measured. The measured velocity was unchanged within 1 from the off resonance value. gains of as much as 23 db were obtained. The observed velocity change for 15 db absorption was 15. A qualitative theory of signal velocity was derived and is in agreement with the observations. The attenuation of microwave phonons due to interaction with Ga acceptors in Ge was observed. All the transverse and longitudinal waves propagating on the 100 and 110 directions show effects due to the impurities. Heat pulses were observed in Bi, Sb and germanium at about 4K. Preliminary data on Bi and Sb leaves the question of whether electrons or phonons are the principal heat carriers unanswered. Heat pulse data for intrinsic germanium indicate that there is considerable phonon scattering though individual phonon modes are distinguishable. Author