Magnetic structures and excitations in CePd2(Al,Ga)(2) series: Development of the "vibron" states

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F17%3A10362624" target="_blank" >RIV/00216208:11320/17:10362624 - isvavai.cz</a>

Result on the web

<a href="http://dx.doi.org/10.1103/PhysRevB.95.085107" target="_blank" >http://dx.doi.org/10.1103/PhysRevB.95.085107</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1103/PhysRevB.95.085107" target="_blank" >10.1103/PhysRevB.95.085107</a>

Result language

angličtina

Original language name

Magnetic structures and excitations in CePd2(Al,Ga)(2) series: Development of the "vibron" states

Original language description

CePd2Al2-xGax compounds crystallizing in the tetragonal CaBe2Ge2-type structure (space group P4/nmm) and undergoing a structural phase transition to an orthorhombic structure (Cmme) at low temperatures were studied by means of neutron scattering. The amplitude-modulated magnetic structure of CePd2Al2 is described by an incommensurate propagation vector (k) over right arrow = (delta(x), 1/2 + delta(y), 0) with delta(x) = 0.06 and delta(y) = 0.04. The magnetic moments order antiferromagnetically within the ab planes stacked along the c axis and are arranged along the direction close to the orthorhombic a axis with a maximum value of 1.5(1) mu(B)/Ce3+. CePd2Ga2 reveals a magnetic structure composed of two components: the first is described by the propagation vector (k) over right arrow (1) = (1/2,1/2,0), and the second one propagates with (k) over right arrow (2) = (0,1/2,0). The magnetic moments of both components are aligned along the same direction-the orthorhombic [100] direction-and their total amplitude varies depending on the mutual phase of magnetic moment components on each Ce site. The propagation vectors (k) over right arrow (1) and (k) over right arrow (2) describe also the magnetic structure of substituted CePd2Al2-xGax compounds, except the one with x = 0.1. CePd2Al1.9Ga0.1 with magnetic structure described by (k) over right arrow and (k) over right arrow (1) stays on the border between pure CePd2Al2 and the rest of the series. Determined magnetic structures are compared with other Ce 112 compounds. Inelastic neutron scattering experiments disclosed three nondispersive magnetic excitations in the paramagnetic state of CePd2Al2, while only two crystal field (CF) excitations are expected from the splitting of ground state J = 5/2 of the Ce3+ ion in a tetragonal/orthorhombic point symmetry. Three magnetic excitations at 1.4, 7.8, and 15.9 meV are observed in the tetragonal phase of CePd2Al2. A structural phase transition to an orthorhombic structure shifts the first excitation up to 3.7 meV, while the other two excitations remain at almost the same energy. The presence of an additional magnetic peak is discussed and described within the Thalmeier-Fulde CF-phonon coupling (i.e., magnetoelastic coupling) model generalized to the tetragonal point symmetry. The second parent compound CePd2Ga2 does not display any sign of additional magnetic excitation. The expected two CF excitations were observed. The development of magnetic excitations in the CePd2Al2-xGax series is discussed and crystal field parameters determined.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

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

Project

Result was created during the realization of more than one project. More information in the Projects tab.

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>S - Specificky vyzkum na vysokych skolach<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2017

Confidentiality

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

Name of the periodical

Physical Review B

ISSN

2469-9950

e-ISSN

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Volume of the periodical

95

Issue of the periodical within the volume

8

Country of publishing house

US - UNITED STATES

Number of pages

15

Pages from-to

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UT code for WoS article

000402194500003

EID of the result in the Scopus database

2-s2.0-85013093624