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Sidan uppdaterades: 2012-09-11 15:12
| Författare |
Joakim Holmlund Christopher S Knee Jakob Andreasson Mats Granath Alexander Litvinchuk Lars Börjesson |
|---|---|
| Publicerad i | Physical Review B |
| Volym | 79 |
| Nummer/häfte | 8 |
| Sidor | 85109 |
| ISSN | 1098-0121 |
| Publiceringsår | 2009 |
| Publicerad vid |
Institutionen för kemi Institutionen för fysik (GU) |
| Sidor | 85109 |
| Språk | en |
| Länkar |
dx.doi.org/10.1103/PhysRevB.79.0851... |
| Ämnesord | antiferromagnetic materials; barium compounds; exchange interactions (electron); high-temperature superconductors; magnetic superconductors; magnons; Raman spectra; strontium compounds |
| Ämneskategorier | Fysik, Den kondenserade materiens fysik, Funktionella material, Materialfysik med ytfysik |
(Sr-2,Ba-2)Cu3O4Cl2 are antiferromagnetic insulators which are akin to the parent compounds of the cuprate superconductors but with two distinct magnetic ordering temperatures related to two magnetic Cu-I and Cu-II spin sublattices. Here we present a study of these materials by means of Raman spectroscopy. Following the temperature and polarization dependence of the data, we readily identify two distinct features at around 3000 and 300 cm(-1) that are related to two-magnon scattering from the two sublattices. The estimated spin-exchange coupling constants for the Cu-I and Cu-II sublattices are found to be J(I)similar to 139-143(132-136) meV and J(II)similar to 14 (11) meV for Sr(Ba) compounds. Moreover, we observe modes at around 480 and 445 cm(-1) for the Sr and Ba containing samples, respectively, which disappears at the ordering temperature of the Cu-II. We argue that these modes may also be of magnetic origin and possibly related to interband transitions between the Cu-I-Cu-II sublattices.
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