No abstract

presented in Fig. 3(b).Weber and Seavey 6 have measured the uniform resonance nuclear relaxation rates in RbMnF 3 over the dc field range of 6-23.5 kOe at T = 4.2°K. They observed a similar frequency dependence of these rates to the dependence shown in Fig. 3(a), namely, a decrease in magnitude with increasing magnon frequency. By extrapolating their results to the frequency range presented in the figure, values are obtained which are higher than our values by two orders of magnitudes. The difference between their values and ours can probably be attributed safely to strain inhomogeneous broadening to which the uniform resonance linewidth, electronic as well as nuclear, is particularly sensitive.Hinderks 7 has recently measured a nuclear relaxation rate of ~0.3 MHz for RbMnF 3 at 1.15°K by employing a photon pump at a frequency of 888 MHz. Since a decrease in the value of the relaxation rate with frequency is expected, this measured value is considered in good agreement with our results. Recent measurements by Hinderks 7 arid by Seavey 8 on CsMnF 3 , also employ-The quasielastic peak directly measures the single-particle structure of the nucleus and dominates the spectrum of high-energy electrons inelastically scattered from nuclei. 1 In addition, quasielastic scattering provides information on nucleon-nucleon correlations 2 and must be understood if one is to examine the usual nuclear sum ing photon pumping, indicate a nuclear relaxation rate lower by an order of magnitude than the relaxation rate of RbMnF 3 . Phonon-nuclearmagnon interaction experiments could therefore be conducted on CsMnF 3 at a much reduced acoustic power.We would like to thank N. F. Foster of Bell Telephone Laboratories for providing the transducers.The cross sections for quasielastic electron scattering from nine target nuclei from lithium to lead have been measured for an electron incident energy of 500 MeV and a scattering angle of 60°. The data are interpreted in terms of a Fermi gas model, yielding the nuclear Fermi momentum as a function of atomic number. The Fermi momentum increases from lithium to calcium and remains roughly constant at about 260 MeV/c from nickel to lead. 445

No abstract

No abstract