EuNi5InH1.5-x (x=0-1.5): hydrogen induced structural and magnetic transitions

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F17%3A10363140" target="_blank" >RIV/00216208:11320/17:10363140 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.1039/c7tc00121e" target="_blank" >http://dx.doi.org/10.1039/c7tc00121e</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1039/c7tc00121e" target="_blank" >10.1039/c7tc00121e</a>

Jazyk výsledku

angličtina

Název v původním jazyce

EuNi5InH1.5-x (x=0-1.5): hydrogen induced structural and magnetic transitions

Popis výsledku v původním jazyce

The new quaternary hydride EuNi5InH1.5 has been obtained by hydrogenation of the intermetallic parent EuNi5In under extremely mild conditions, hence, at room temperature and low hydrogen pressure. Hydrogenation at slightly elevated temperatures and pressures allows for the growth of large crystals, which is a rare observation for intermetallic hydrides. EuNi5InH1.5 crystallizes in its own structure type (hP17, P (6) over bar m2, a = 4.9437(6), c = 10.643(1) angstrom) with a unique arrangement of the intermetallic host. The hydrogen atoms prefer Ni-surrounded positions, occupying {EuNi3} and {Eu2Ni2} tetrahedral voids in the structure. Upon hydrogenation of EuNi5In an anisotropic volume expansion accompanied with a decrease of symmetry is observed. Magnetic measurements reveal antiferromagnetic ordering in the hydride below 4 K and indicate an intermediate +II/+III oxidation state for Eu both in the intermetallic phase and the hydride. X-ray photoemission spectroscopy confirms the existence of the two different oxidation states of Eu. The hydrogenation does not affect the oxidation state of Eu and the type of magnetic ordering, but exerts a strong influence on the transition temperature, crystal structure, mechanical and electrical properties. Crystallographic analysis suggests that Eu(II) and Eu(III) do not order but rather mix homogeneously on crystallographic sites. Electronic structure calculations reveal the metallic character of the hydride with several different types of chemical bonding interactions being present in the compound ranging from the formally ionic EuH to covalent NiH and delocalized metalmetal. Geometry optimization confirm the thermodynamic instability of the intermetallic host lattice for the hydride and supports a transformation into the parental structure as observed experimentally.

Název v anglickém jazyce

EuNi5InH1.5-x (x=0-1.5): hydrogen induced structural and magnetic transitions

Popis výsledku anglicky

The new quaternary hydride EuNi5InH1.5 has been obtained by hydrogenation of the intermetallic parent EuNi5In under extremely mild conditions, hence, at room temperature and low hydrogen pressure. Hydrogenation at slightly elevated temperatures and pressures allows for the growth of large crystals, which is a rare observation for intermetallic hydrides. EuNi5InH1.5 crystallizes in its own structure type (hP17, P (6) over bar m2, a = 4.9437(6), c = 10.643(1) angstrom) with a unique arrangement of the intermetallic host. The hydrogen atoms prefer Ni-surrounded positions, occupying {EuNi3} and {Eu2Ni2} tetrahedral voids in the structure. Upon hydrogenation of EuNi5In an anisotropic volume expansion accompanied with a decrease of symmetry is observed. Magnetic measurements reveal antiferromagnetic ordering in the hydride below 4 K and indicate an intermediate +II/+III oxidation state for Eu both in the intermetallic phase and the hydride. X-ray photoemission spectroscopy confirms the existence of the two different oxidation states of Eu. The hydrogenation does not affect the oxidation state of Eu and the type of magnetic ordering, but exerts a strong influence on the transition temperature, crystal structure, mechanical and electrical properties. Crystallographic analysis suggests that Eu(II) and Eu(III) do not order but rather mix homogeneously on crystallographic sites. Electronic structure calculations reveal the metallic character of the hydride with several different types of chemical bonding interactions being present in the compound ranging from the formally ionic EuH to covalent NiH and delocalized metalmetal. Geometry optimization confirm the thermodynamic instability of the intermetallic host lattice for the hydride and supports a transformation into the parental structure as observed experimentally.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10302 - Condensed matter physics (including formerly solid state physics, supercond.)

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2017

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Journal of Materials Chemistry C

ISSN

2050-7526

e-ISSN

—

Svazek periodika

5

Číslo periodika v rámci svazku

12

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

13

Strana od-do

2994-3006

Kód UT WoS článku

000397963500002

EID výsledku v databázi Scopus

2-s2.0-85016112443