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Influence of oxygen isotope exchange on the ground state of manganites

V. N. Smolyaninova·Amlan Biswas·P. Fournier·S. Lofland·X. Zhang·Guo-meng Zhao·R. L. Greene
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Abstract

We report a study of oxygen isotope effects on low temperature specific heat, magnetization, and resistivity of La$_{1-x}$Ca$_{x}$MnO$_{3}$ and (La$_{1-y}$Pr$_{y})_{0.67}$Ca$_{0.33}$MnO$_{3}$. For the metallic compositions of La$_{1-x}$Ca$_{x}$MnO$_{3}$ and for charge-ordered La$_{0.5}$Ca$_{0.5}$MnO$_{3}$ no change in low temperature specific heat has been detected with $^{16}$O -$^{18}$O exchange, while compounds of (La$_{1-y}$Pr$_{y})_{0.67}$Ca$_{0.33}$MnO$_{3}$ (0.4<y<0.6) show a significant change in low temperature properties. The low temperature specific heat indicates a presence of the charge-ordered phase even in compositions of (La$_{1-y}$Pr$_{y})_{0.67}$Ca$_{0.33}$MnO$_{3}$ which are metallic at low temperatures. We suggest that the changes induced by the oxygen isotope exchange are caused by an increase of the charge-ordered phase in $^{18}$O samples.

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V. N. Smolyaninova, Amlan Biswas, P. Fournier, S. Lofland, X. Zhang, Guo-meng Zhao, R. L. Greene. 2001-07-11. Influence of oxygen isotope exchange on the ground state of manganites. https://doi.org/10.1103/physrevb.65.104419

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