Phonon and magnetic dimer excitations in Febased S =2 spinladder compound BaFe2Se2O
Abstract
Raman scattering spectra of the new Febased S =2 spinladder compound BaFe2Se2O are measured in a temperature range between 15 and 623 K. All six A_{1g} and two B_{1g} Raman active modes of BaFe2Se2O, predicted by the factorgroup analysis, have been experimentally observed at energies that are in a rather good agreement with the lattice dynamics calculation. The antiferromagnetic longrange spin ordering in BaFe2Se2O below T_{N}=240 K leaves a fingerprint both in the A_{1g} and B_{1g} phonon mode linewidth and energy. In the energy range between 400 and 650 cm^{1} we have observed a magnetic excitation related structure in the form of a magnon continuum, with the peaks corresponding to the singularities in the onedimensional density of magnon states. The onset value of magnetic continuum (2Δ_{S}) is found at about 437 cm^{1} at 15 K. The magnetic continuum disappears at about 623 K, which led us to conclude that the shortrange magnetic ordering in BaFe2Se2O exists apparently up to 2.6T_{N}.
 Publication:

Physical Review B
 Pub Date:
 January 2014
 DOI:
 10.1103/PhysRevB.89.014301
 arXiv:
 arXiv:1312.6844
 Bibcode:
 2014PhRvB..89a4301P
 Keywords:

 78.30.j;
 75.30.Ds;
 63.20.D;
 74.70.Xa;
 Infrared and Raman spectra;
 Spin waves;
 Phonon states and bands normal modes and phonon dispersion;
 Condensed Matter  Materials Science;
 Condensed Matter  Strongly Correlated Electrons
 EPrint:
 Phys. Rev. B 89, 014301 (2014)