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Ca$_2$MnO$_4$ structural path: Following the negative thermal expansion at the local scale
The oxygen octahedral rotations in Ca$_2$MnO$_4$, the first member of the $\textrm{Ca O ( CaMnO}_3)_n$ Ruddlesden-Popper family, is probed through a set of complementary techniques, including temperature-dependent neutron and x-ray diffraction, combined with local probe studies and ab initio calcula...
Autores principales: | , , , , , , , , , , |
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Lenguaje: | eng |
Publicado: |
2020
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Materias: | |
Acceso en línea: | https://dx.doi.org/10.1103/physrevb.102.104115 http://cds.cern.ch/record/2781488 |
_version_ | 1780971946385604608 |
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author | Rocha-Rodrigues, Pedro Santos, Samuel S M Oliveira, Gonçalo N P Leal, Tiago Miranda, Ivan P dos Santos, António M Correia, João G Assali, Lucy V C Petrilli, Helena M Araújo, João P Lopes, Armandina M L |
author_facet | Rocha-Rodrigues, Pedro Santos, Samuel S M Oliveira, Gonçalo N P Leal, Tiago Miranda, Ivan P dos Santos, António M Correia, João G Assali, Lucy V C Petrilli, Helena M Araújo, João P Lopes, Armandina M L |
author_sort | Rocha-Rodrigues, Pedro |
collection | CERN |
description | The oxygen octahedral rotations in Ca$_2$MnO$_4$, the first member of the $\textrm{Ca O ( CaMnO}_3)_n$ Ruddlesden-Popper family, is probed through a set of complementary techniques, including temperature-dependent neutron and x-ray diffraction, combined with local probe studies and ab initio calculations. Here we demonstrate the enhancement of the uniaxial negative thermal expansion coefficient from $-1.26 \pm 0.25$ to $-21 \pm 1.8$ ppm/K at the second order $I4_1/acd$ to $I4/mmm$ structural phase transition, providing direct evidence for the corkscrew atomic mechanism. We establish, also, that the predicted $I4/mmm$ high symmetry is attained around 1050 K. At lower temperatures, within the 10–1000 K temperature range, our first-principles calculations and detailed analysis of the Ca local environment reveals that the reported $Aba2$ structural phase, coexisting with the $I4_1/acd$ one, cannot describe correctly this compound. On the other hand, our data allow for the coexistence of the locally identical $I4_1/acd$ and $Acam$ structural phases. |
id | cern-2781488 |
institution | Organización Europea para la Investigación Nuclear |
language | eng |
publishDate | 2020 |
record_format | invenio |
spelling | cern-27814882021-09-21T09:10:57Zdoi:10.1103/physrevb.102.104115http://cds.cern.ch/record/2781488engRocha-Rodrigues, PedroSantos, Samuel S MOliveira, Gonçalo N PLeal, TiagoMiranda, Ivan Pdos Santos, António MCorreia, João GAssali, Lucy V CPetrilli, Helena MAraújo, João PLopes, Armandina M LCa$_2$MnO$_4$ structural path: Following the negative thermal expansion at the local scaleNuclear Physics - ExperimentThe oxygen octahedral rotations in Ca$_2$MnO$_4$, the first member of the $\textrm{Ca O ( CaMnO}_3)_n$ Ruddlesden-Popper family, is probed through a set of complementary techniques, including temperature-dependent neutron and x-ray diffraction, combined with local probe studies and ab initio calculations. Here we demonstrate the enhancement of the uniaxial negative thermal expansion coefficient from $-1.26 \pm 0.25$ to $-21 \pm 1.8$ ppm/K at the second order $I4_1/acd$ to $I4/mmm$ structural phase transition, providing direct evidence for the corkscrew atomic mechanism. We establish, also, that the predicted $I4/mmm$ high symmetry is attained around 1050 K. At lower temperatures, within the 10–1000 K temperature range, our first-principles calculations and detailed analysis of the Ca local environment reveals that the reported $Aba2$ structural phase, coexisting with the $I4_1/acd$ one, cannot describe correctly this compound. On the other hand, our data allow for the coexistence of the locally identical $I4_1/acd$ and $Acam$ structural phases.oai:cds.cern.ch:27814882020 |
spellingShingle | Nuclear Physics - Experiment Rocha-Rodrigues, Pedro Santos, Samuel S M Oliveira, Gonçalo N P Leal, Tiago Miranda, Ivan P dos Santos, António M Correia, João G Assali, Lucy V C Petrilli, Helena M Araújo, João P Lopes, Armandina M L Ca$_2$MnO$_4$ structural path: Following the negative thermal expansion at the local scale |
title | Ca$_2$MnO$_4$ structural path: Following the negative thermal expansion at the local scale |
title_full | Ca$_2$MnO$_4$ structural path: Following the negative thermal expansion at the local scale |
title_fullStr | Ca$_2$MnO$_4$ structural path: Following the negative thermal expansion at the local scale |
title_full_unstemmed | Ca$_2$MnO$_4$ structural path: Following the negative thermal expansion at the local scale |
title_short | Ca$_2$MnO$_4$ structural path: Following the negative thermal expansion at the local scale |
title_sort | ca$_2$mno$_4$ structural path: following the negative thermal expansion at the local scale |
topic | Nuclear Physics - Experiment |
url | https://dx.doi.org/10.1103/physrevb.102.104115 http://cds.cern.ch/record/2781488 |
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