TY - JOUR
T1 - Magnon spectra and strong spin-lattice coupling in magnetically frustrated MnB2 O4 (B=Mn,V)
T2 - Inelastic light-scattering studies
AU - Gleason, S. L.
AU - Byrum, T.
AU - Gim, Y.
AU - Thaler, A.
AU - Abbamonte, P.
AU - Macdougall, G. J.
AU - Martin, L. W.
AU - Zhou, H. D.
AU - Cooper, S. L.
PY - 2014/4/3
Y1 - 2014/4/3
N2 - The ferrimagnetic spinels MnB2O4 (B=Mn,V) exhibit a similar series of closely spaced magnetic and structural phase transitions at low temperatures, reflecting both magnetic frustration and a strong coupling between the spin and lattice degrees of freedom. Careful studies of excitations in MnB2O4 (B=Mn,V), and the evolution of these excitations with temperature, are important for obtaining a microscopic description of the role that magnetic excitations and spin-lattice coupling play in the low-temperature phase transitions of these materials. We report an inelastic light (Raman) scattering study of the temperature and magnetic-field dependences of one- and two-magnon excitations in MnV2O4 and Mn3O4. We observe a pair of q=0 one-magnon modes at 74 and 81 cm-1 in MnV2O4, which is in contrast with the single 80-cm-1 q=0 magnon that has been reported for MnV2O4 based on previous neutron-scattering measurements and spin-wave calculations. Additionally, we find that the two-magnon energy of MnV2O4 decreases ("softens") with decreasing temperature below TN, which we attribute to strong coupling between magnetic and vibrational excitations near the zone boundary.
AB - The ferrimagnetic spinels MnB2O4 (B=Mn,V) exhibit a similar series of closely spaced magnetic and structural phase transitions at low temperatures, reflecting both magnetic frustration and a strong coupling between the spin and lattice degrees of freedom. Careful studies of excitations in MnB2O4 (B=Mn,V), and the evolution of these excitations with temperature, are important for obtaining a microscopic description of the role that magnetic excitations and spin-lattice coupling play in the low-temperature phase transitions of these materials. We report an inelastic light (Raman) scattering study of the temperature and magnetic-field dependences of one- and two-magnon excitations in MnV2O4 and Mn3O4. We observe a pair of q=0 one-magnon modes at 74 and 81 cm-1 in MnV2O4, which is in contrast with the single 80-cm-1 q=0 magnon that has been reported for MnV2O4 based on previous neutron-scattering measurements and spin-wave calculations. Additionally, we find that the two-magnon energy of MnV2O4 decreases ("softens") with decreasing temperature below TN, which we attribute to strong coupling between magnetic and vibrational excitations near the zone boundary.
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U2 - 10.1103/PhysRevB.89.134402
DO - 10.1103/PhysRevB.89.134402
M3 - Article
AN - SCOPUS:84899715814
SN - 1098-0121
VL - 89
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
IS - 13
M1 - 134402
ER -