Phonon-Magnon Interaction in Magnetic Crystals. II. Antiferromagnetic Systems

摘要: A theoretical study of phonon-magnon interaction in antiferromagnets is made on the basis a microscopic mechanism developed earlier. The mechanism, which essence takes into account mixing excited orbital states with ground magnetic ions owing to crystal field oscillations, applied can be subdivided two interpenetrating identical sublattices coupled antiferromagnetically.The terms for one-phonon direct processes are first derived following methods previous paper. expressions relaxation times then obtained these low-temperature limit. It found that time ${\ensuremath{\tau}}_{\mathrm{sp}}$ inversely proportional fifth power temperature (${T}^{5}$) this region. Numerical estimate Mn${\mathrm{F}}_{2}$ at 10\ifmmode^\circ\else\textdegree\fi{}K gives tentative value ${\ensuremath{\tau}}_{\mathrm{sp}}\ensuremath{\sim}{10}^{\ensuremath{-}8}$ sec.