MPI für Festkörperforschung / FKF Publikationen 2006 |
|Fe3GeTe2 and Ni3GeTe2 – Two new layered transition-metal compounds: Crystal structures, HRTEM investigations, and magnetic and electrical properties|
|Authors:||Deiseroth, H. J.; Aleksandrov, K.; Reiner, C.; Kienle, L.; Kremer, R. K.|
|Date of Publication (YYYY-MM-DD):||2006|
|Title of Journal:||European Journal of Inorganic Chemistry|
|Issue / Number:||8|
|Abstract / Description:||Fe3GeTe2 and Ni3GeTe2 are two new air-stable, black-metallic solids.
They were characterized by single-crystal X-ray crystallography, high
resolution transmission electron microscopy (HRTEM), and preliminary
magnetic measurements. Both compounds crystallize in the hexagonal
system [P6(3)/ mmc, Z = 2; Fe3GeTe2: a = 399.1(1) pm, c = 1633(3) pm;
Ni3GeTe2: a = 391.1(1) pm, c = 1602.0(3) pm], and represent a new
structure type with a pronounced macroscopic and microscopic layer
character. They show close structural relationships to iron/nickel
germanium alloys. Each layer in the title compounds represents a
sandwich structure with two layers of tellurium atoms covering a
triple-layer Fe3Ge (Ni3Ge) substructure on both sides. Assuming full
occupancies for the Fe and Ni sites, a mixed-valence formulation for
the transition-metal atoms according to (M2+)(M3+)(2)(Ge4-)-(Te2-)(2)
(M = Fe, Ni) may be concluded. A slightly reduced occupancy for one
Fe/Ni position, however, indicates a more complicated local structural
situation. This is confirmed by weak residual electron density in the
van der Waals gap and by the results of detailed HRTEM and
electron-diffraction experiments for Ni3GeTe2. The latter results show
variations in the arrangement of Ni atoms, as well as vacancies and a
misfit of in-plane disordered hexagonal layers. Fe3GeTe2 shows
Curie-Weiss behavior above and ferromagnetism below 230 K, while
Ni3GeTe2 exhibits temperature-independent paramagnetism in the measured
temperature range and a metallic behavior of the electrical resistance.
(c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006.
|Free Keywords:||layered compounds; crystal structures; iron germanium telluride;
magnetism; electron microscopy; conductivity
|External Publication Status:||published|
|Communicated by:||N. N.|
|Affiliations:||MPI für Festkörperforschung|
|External Affiliations:||Univ Siegen, D-57068 Siegen, Germany.
; Max Planck Inst Festkorperforsch, D-70569 Stuttgart, Germany.
|Identifiers:||ISI:000236981100004 [ID No:1] |
ISSN:1434-1948 [ID No:2]
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