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Advances in Condensed Matter Physics
Volume 2011 (2011), Article ID 178190, 5 pages
http://dx.doi.org/10.1155/2011/178190
Research Article

A Precise Measurement of the Oxygen Isotope Effect on the Néel Temperature in Cuprates

1Physics Department, Technion-Israel Institute of Technology, Haifa 32000, Israel
2Rutherford Appleton Laboratory, Chilton Didcot, Oxfordshire OX11 0QX, UK

Received 29 December 2010; Accepted 8 March 2011

Academic Editor: Ashok Chatterjee

Copyright © 2011 E. Amit et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A limiting factor in the ability to interpret isotope effect measurements in cuprates is the absence of sufficiently accurate data for the whole phase diagram; there is precise data for 𝑇 𝑐 , but not for the antiferromagnetic transition temperature 𝑇 𝑁 . Extreme sensitivity of 𝑇 𝑁 to small changes in the amount of oxygen in the sample is the major problem. This problem is solved here by using the novel compound ( C a 0 . 1 L a 0 . 9 )( B a 1 . 6 5 L a 0 . 3 5 ) C u 3 O 𝑦 for which there is a region where 𝑇 𝑁 is independent of oxygen doping. Meticulous measurements of 𝑇 𝑁 for samples with 1 6 O and 1 8 O find the absence of an oxygen isotope effect on 𝑇 𝑁 with unprecedented accuracy. A possible interpretation of our finding and existing data is that isotope substitution affects the normal state charge carrier density.