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Raman Scattering by Two-Magnon Excitations in FeBO 3

1974; Physical Society of Japan; Volume: 37; Issue: 2 Linguagem: Inglês

10.1143/jpsj.37.354

1347-4073

Naoki Koshizuka, Takashi Okuda, Masayuki Udagawa, Tachiro Tsushima,

X-ray Diffraction in Crystallography

An experimental investigation on Raman scattering from magnons and phonons has been made for FeBO 3 . A Raman line at 537 cm -1 is confirmed as due to two-magnon excitations from a comparison of the spectra of pure FeBO 3 crystals with In-substituted ones, as well as from the temperature dependence of the line of pure FeBO 3 . Selection rules for the two-magnon excitations are obtained using the spin-dependent electric polarizability theory. An analysis of the two-magnon spectrum leads to give the exchange parameters in the -2 J i j ( S i · S j ) type interaction. The first neighbor intersublattice exchange interaction J A B =-9.6 cm -1 . The second neighbor intersublattice interaction J A ' B and the first neighbor intrasublattice interaction J B ' B are estimated to be -2.0 cm -1 on the assumption that J A ' B ∼ J B ' B . Thermal behaviors of the phonon lines are also studied in comparison with those in CaCO 3 .