Observation of incommensurate two-dimensional magnetic correlations in La(1.8)Sr(0.2)NiO(4)
Following earlier work on pure La(2)NiO(4), a study of the Sr doped compound has begun. In the initial diffraction studies no evidence was found for magnetic ordering in La(1.8)Sr(0.2)NiO(4), suggesting that the material became a spin glass at low T, with a freezing temperature of about 17 K. A large (0.25 cc) single crystal has now been produced and an experiment performed at the ILL, Grenoble, on a cold-source triple axis (IN12). The significant results are: (1) Short-range magnetic correlations that are principally 2-dimensional in nature appear at low temperature. (2) These effects have a maximum at the lowest temperature examined and are within the Ni-O plane. (3) There is very little variation of the magnetic intensity perpendicular to the Ni-O planes. (4) The position of the peak is incommensurate with q = [0.825, 0, 0]. Neither the width nor the position of the peak changes with temperature. (5) As the temperature is raised, the correlations rapidly become inelastic and move outside the energy window of the spectrometer (0.34 meV). These results are particularly interesting in view of the large amount of work performed on the analogous cuprate systems. In the latter, incommensurate correlations can be seen only when the material is superconducting. However, La(1.8)Sr(0.2)NiO(4) is a good insulator at all temperatures.
Bibliographic Reference: Paper presented: International Conference on Neutron Scattering, Oxford (GB), Aug. 27-30, 1991
Availability: Available from (1) as Paper EN 36131 ORA
Record Number: 199111504 / Last updated on: 1994-12-02
Original language: en
Available languages: en