Phase transitions of LnAs (Ln = Pr, Nd, Sm, Gd, Dy and Ho) with NaCl-type structure at high pressures

Citation
I. Shirotani et al., Phase transitions of LnAs (Ln = Pr, Nd, Sm, Gd, Dy and Ho) with NaCl-type structure at high pressures, J PHYS-COND, 13(9), 2001, pp. 1939-1946
Citations number
13
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
JOURNAL OF PHYSICS-CONDENSED MATTER
ISSN journal
0953-8984 → ACNP
Volume
13
Issue
9
Year of publication
2001
Pages
1939 - 1946
Database
ISI
SICI code
0953-8984(20010305)13:9<1939:PTOL(=>2.0.ZU;2-Y
Abstract
By use of synchrotron radiation the powder x-ray diffraction of lanthanide monoarsenides LnAs (Ln = Pr, Nd, Sm, Gd, Dy and Ho) with a NaCl-type struct ure has been studied up to 60 GPa at room temperature. First-order phase tr ansitions with crystallographic change were found at around 27.1 GPa for Pr As, 24.2 GPa for NdAs and 32.1 GPa for SmAs. The high-pressure form of the lighter LnAs (Ln = Pr, Nd and Sm) is a tetragonal structure and can be view ed as a distorted CsCl-type structure. The atoms in the tetragonal structur e are located at Ln: 0, 0, 0; As: 1/2, 1/2, 1/2, The space group is P4/mmm. Pressure-induced phase transitions of the heavier LnAs (Ln = Gd, Dy and Ho ) with many f electrons occur at around 36 GPa for GdAs, 44 GPa for DyAs an d 46 GPa for HoAs. The structure of these high-pressure phases is unknown. The high-pressure structural behaviour of LnAs (Ln = Pr, Nd, Sm, Gd, Dy and Ho) with the NaCl-type structure is discussed.