The effect of Sr impurity disorder on the magnetic correlations of La_2-xSr_xCuO_4.
Abstract
We examine the low--temperature magnetic properties of moderately doped LaSrCuO paying particular attention to the spin--glass (SG) phase and the C-IC transition as they are affected by Sr impurity disorder. New measurements of the low--temperature susceptibility in the SG phase show an increase of an anomalously small Curie constant with doping. This behaviour is explained in terms of our theoretical work that finds small clusters of AFM correlated regions separated by disordered domain walls. The domain walls lead to a percolating sequence of paths connecting the impurities. We predict that for this spin morphology the Curie constant should scale as 1/(2 ξ(x,T=0)^2), a result that is quantitatively in agreement with experiment. Also, we find that the magnetic correlations in the ground states in the SG phase are commensurate, and that this behaviour should persist at higher temperatures where the holes should move along the domain walls. However, our results show that incommensurate correlations develop continuously around x = 0.05 doping, consistent with recent measurements by Yamada. Coupling this understanding of the magnetic correlations with the observed transport features, it is clear that impurity effects strongly influence the physics of LaSrCuO.
- Publication:
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APS March Meeting Abstracts
- Pub Date:
- March 1997
- Bibcode:
- 1997APS..MAR.G1001G