Spin gaps and magnetic structure of NaxCoO2
We present two experiments that provide information on spin anisotropy and the magnetic structure of NaxCoO2. First, we report low-energy neutron inelastic scattering measurements of the zone-center magnetic excitations in the magnetically ordered phase of Na0.75CoO2. The energy spectra suggest the...
| Автори: | , , , , , , |
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| Формат: | Journal article |
| Мова: | English |
| Опубліковано: |
2005
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| _version_ | 1826279563459559424 |
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| author | Helme, L Boothroyd, A Coldea, R Prabhakaran, D Stunault, A McIntyre, G Kernavanois, N |
| author_facet | Helme, L Boothroyd, A Coldea, R Prabhakaran, D Stunault, A McIntyre, G Kernavanois, N |
| author_sort | Helme, L |
| collection | OXFORD |
| description | We present two experiments that provide information on spin anisotropy and the magnetic structure of NaxCoO2. First, we report low-energy neutron inelastic scattering measurements of the zone-center magnetic excitations in the magnetically ordered phase of Na0.75CoO2. The energy spectra suggest the existence of two gaps, and are very well fitted by a spin-wave model with both in-plane and out-of-plane anisotropy terms. The gap energies decrease with increasing temperature and both gaps are found to have closed when the temperature exceeds the magnetic ordering temperature T_m~22 K. Secondly, we present neutron diffraction studies of Na0.85CoO2 with a magnetic field applied approximately parallel to the c axis. For fields in excess of ~8T a magnetic Bragg peak was observed at the (0,0,3) position in reciprocal space. We interpret this as a spin-flop transition of the A-type antiferromagnetic structure, and we show that the spin-flop field is consistent with the size of the anisotropy gap. |
| first_indexed | 2024-03-07T00:00:37Z |
| format | Journal article |
| id | oxford-uuid:75d06d08-ad0b-4be2-aefb-ff72f380ac74 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T00:00:37Z |
| publishDate | 2005 |
| record_format | dspace |
| spelling | oxford-uuid:75d06d08-ad0b-4be2-aefb-ff72f380ac742022-03-26T20:11:45ZSpin gaps and magnetic structure of NaxCoO2Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:75d06d08-ad0b-4be2-aefb-ff72f380ac74EnglishSymplectic Elements at Oxford2005Helme, LBoothroyd, AColdea, RPrabhakaran, DStunault, AMcIntyre, GKernavanois, NWe present two experiments that provide information on spin anisotropy and the magnetic structure of NaxCoO2. First, we report low-energy neutron inelastic scattering measurements of the zone-center magnetic excitations in the magnetically ordered phase of Na0.75CoO2. The energy spectra suggest the existence of two gaps, and are very well fitted by a spin-wave model with both in-plane and out-of-plane anisotropy terms. The gap energies decrease with increasing temperature and both gaps are found to have closed when the temperature exceeds the magnetic ordering temperature T_m~22 K. Secondly, we present neutron diffraction studies of Na0.85CoO2 with a magnetic field applied approximately parallel to the c axis. For fields in excess of ~8T a magnetic Bragg peak was observed at the (0,0,3) position in reciprocal space. We interpret this as a spin-flop transition of the A-type antiferromagnetic structure, and we show that the spin-flop field is consistent with the size of the anisotropy gap. |
| spellingShingle | Helme, L Boothroyd, A Coldea, R Prabhakaran, D Stunault, A McIntyre, G Kernavanois, N Spin gaps and magnetic structure of NaxCoO2 |
| title | Spin gaps and magnetic structure of NaxCoO2 |
| title_full | Spin gaps and magnetic structure of NaxCoO2 |
| title_fullStr | Spin gaps and magnetic structure of NaxCoO2 |
| title_full_unstemmed | Spin gaps and magnetic structure of NaxCoO2 |
| title_short | Spin gaps and magnetic structure of NaxCoO2 |
| title_sort | spin gaps and magnetic structure of naxcoo2 |
| work_keys_str_mv | AT helmel spingapsandmagneticstructureofnaxcoo2 AT boothroyda spingapsandmagneticstructureofnaxcoo2 AT coldear spingapsandmagneticstructureofnaxcoo2 AT prabhakarand spingapsandmagneticstructureofnaxcoo2 AT stunaulta spingapsandmagneticstructureofnaxcoo2 AT mcintyreg spingapsandmagneticstructureofnaxcoo2 AT kernavanoisn spingapsandmagneticstructureofnaxcoo2 |