Unusual temperature dependence of the oxygen-isotope effect on the exchange-energy ofLa1−xCaxMnO3at high temperatures

2008/02/28 by Guo-meng Zhao, Guo‐meng Zhao, John Mann · 1 citation
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Magnetic and transport properties of perovskites and related materials #Rare-earth and actinide compounds #cond-mat.str-el

paper · pdf · doi:10.1103/physrevb.77.100406

4 pages, 5 figures

arxiv created 2008/02/28 · openalex publication_date 2008/03/28 · arxiv updated 2010/03/11 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28

Abstract

We report magnetic susceptibility \ensuremathχ(T) measurements on oxygen-isotope exchanged La_1\ensuremath-xCa_xMnO_3+y up to 700\phantom\rule0.3em0exK. The 1∕\ensuremathχ(T) data show that the ferromagnetic exchange-energy J strongly depends on the oxygen-isotope mass. The isotope effect on J decreases with temperature up to 400\phantom\rule0.3em0exK and then increases again with temperature above 400\phantom\rule0.3em0exK. This unusual temperature dependence of the isotope effect cannot be explained by existing theories of the colossal magnetoresistance effect for doped manganites. The present results thus provide essential constraints on the physics of manganites.

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