BaAl<sub>4</sub> Derivative Phases in the Sections {La,Ce}Ni<sub>2</sub>Si<sub>2</sub>-{La,Ce}Zn<sub>2</sub>Si<sub>2</sub>

Author(s)
Fainan Failamani, Zahida Malik, Leonid P. Salamakha, Friedrich Kneidinger, Andrij Grytsiv, Herwig Michor, Ernst Bauer, Gerald Giester, Peter Franz Rogl
Abstract

Phase relations and crystal structures have been evaluated within the sections LaNi

2Si

2-LaZn

2Si

2 and CeNi

2Si

2-CeZn

2Si

2 at 800 °C using electron microprobe analysis and X-ray powder and single crystal structure analyses. Although the systems La-Zn-Si and Ce-Zn-Si at 800 °C do not reveal compounds such as "LaZn

2Si

2" or "CeZn

2Si

2", solid solutions {La,Ce}(Ni

1-xZn

x)

2Si

2 exist with the Ni/Zn substitution starting from {La,Ce}Ni

2Si

2 (ThCr

2Si

2-type; I4/mmm) up to x = 0.18 for Ce(Ni

1-xZn

x)

2Si

2 and x = 0.125 for La(Ni

1-xZn

x)

2Si

2. For higher Zn-contents 0.25 ≤ x ≤ 0.55 the solutions adopt the CaBe

2Ge

2-type (P4/nmm). The investigations are backed by single crystal X-ray diffraction data for Ce(Ni

0.61Zn

0.39)

2Si

2 (P4/nmm; a = 0.41022(1) nm, c = 0.98146(4) nm; R

F = 0.012) and by Rietveld refinement for La(Ni

0.56Zn

0.44)

2Si

2 (P4/nmm; a = 0.41680(6) nm, c = 0.99364(4) nm; R

F = 0.043). Interestingly, the Ce-Zn-Si system contains a ternary phase CeZn

2(Si

1-xZn

x)

2 of the ThCr

2Si

2 structure type (0.25 ≤ x ≤ 0.30 at 600 °C), which forms peritectically at T = 695 °C but does not include the composition "CeZn

2Si

2". The primitive high temperature tetragonal phase with the CaBe

2Ge

2-type has also been observed for the first time in the Ce-Ni-Si system at CeNi

2+xSi

2-x, x = 0.33 (single crystal data, P4/nmm; a = 0.40150(2) nm, c = 0.95210(2) nm; R

F = 0.0163). Physical properties (from 400 mK to 300 K) including specific heat, electrical resistivity and magnetic susceptibility have been elucidated for Ce(Ni

0.61Zn

0.39)

2Si

2 and La(Ni

0.56Zn

0.44)

2Si

2. Ce(Ni

0.61Zn

0.39)

2Si

2 exhibits a Kondo-type ground state. Low temperature specific heat data of La(Ni

0.56Zn

0.44)

2Si

2 suggest a spin fluctuation scenario with an enhanced value of the Sommerfeld constant.

Organisation(s)
Department of Materials Chemistry, Department of Mineralogy and Crystallography
External organisation(s)
Technische Universität Wien, Christian Doppler Research Association
Journal
Dalton Transactions
Volume
45
Pages
5262-5273
No. of pages
12
ISSN
1477-9226
DOI
https://doi.org/10.1039/c5dt04705f
Publication date
03-2016
Peer reviewed
Yes
Austrian Fields of Science 2012
104017 Physical chemistry, 104011 Materials chemistry, 105113 Crystallography
Keywords
Portal url
https://ucrisportal.univie.ac.at/en/publications/baal4-derivative-phases-in-the-sections-laceni2si2lacezn2si2(95982e82-770c-4aeb-9d0c-dcda02899af7).html