Cargando…

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...

Descripción completa

Detalles Bibliográficos
Autores principales: 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
Lenguaje:eng
Publicado: 2020
Materias:
Acceso en línea:https://dx.doi.org/10.1103/physrevb.102.104115
http://cds.cern.ch/record/2781488
_version_ 1780971946385604608
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
work_keys_str_mv AT rocharodriguespedro ca2mno4structuralpathfollowingthenegativethermalexpansionatthelocalscale
AT santossamuelsm ca2mno4structuralpathfollowingthenegativethermalexpansionatthelocalscale
AT oliveiragoncalonp ca2mno4structuralpathfollowingthenegativethermalexpansionatthelocalscale
AT lealtiago ca2mno4structuralpathfollowingthenegativethermalexpansionatthelocalscale
AT mirandaivanp ca2mno4structuralpathfollowingthenegativethermalexpansionatthelocalscale
AT dossantosantoniom ca2mno4structuralpathfollowingthenegativethermalexpansionatthelocalscale
AT correiajoaog ca2mno4structuralpathfollowingthenegativethermalexpansionatthelocalscale
AT assalilucyvc ca2mno4structuralpathfollowingthenegativethermalexpansionatthelocalscale
AT petrillihelenam ca2mno4structuralpathfollowingthenegativethermalexpansionatthelocalscale
AT araujojoaop ca2mno4structuralpathfollowingthenegativethermalexpansionatthelocalscale
AT lopesarmandinaml ca2mno4structuralpathfollowingthenegativethermalexpansionatthelocalscale