Antiferromagnetic fluctuations in FeSe1-xTex0.92 x = 0.75, 1 observed by inelastic neutron scattering - Condensed Matter > Strongly Correlated ElectronsReport as inadecuate




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Abstract: Motivated by the discovery of superconductivity in F-doped LaFeAsO, weinvestigated the magnetic fluctuations in a related compound FeSe1-xTex0.92x = 0.75, 1 using neutron scattering techniques. Non-superconducting FeTe0.92shows antiferromagnetic AF ordering with the ordering vector |Q| = 0.97 A-1Q = 0.5,0,0.5 at TN ~ 70 K and a structural transition between tetragonaland monoclinic phases. In the AF monoclinic phase, the low-energy spectralweight is suppressed, indicating a possible gap formation. On the other hand,in the paramagnetic tetragonal phase, we observed a pronounced magneticfluctuation around at |Q| ~ 0.92 A-1, which is slightly smaller than thecommensurate value. In FeSe0.25Te0.750.92, which does not show magneticordering and shows superconductivity at Tc ~ 8 K, we observed that a magneticfluctuation is located at |Q| ~ 0.9 A-1 at low energies and shifts to a highervalue of |Q| ~ 1.2 A-1 at higher energies. The latter value is close to areciprocal lattice vector Q = 0.5,0.5,0.5 or 0.5,0.5,0, where the AFfluctuations are observed in other FeAs-based materials. The existence of thiscommon characteristic in different Fe-based superconductors suggests that theAF fluctuations may play a important role in superconductivity.



Author: Satoshi Iikubo, Masaki Fujita, Seiji Niitaka, Hidenori Takagi

Source: https://arxiv.org/







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