Nickel deficiency in RENi{sub 2-x}P{sub 2} (RE=La, Ce, Pr). Combined crystallographic and physical property studies

Journal Article · Mon Jun 15 04:00:00 EDT 2009 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2009.03.014· OSTI ID:21370438

Bobev, Svilen ^[1]; Xia, Sheng-qing ^[1]; Bauer, Eric D; Ronning, Filip; Thompson, Joe D; Sarrao, John L ^[2]

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1. Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716 (United States)
2. Materials Physics and Applications Division (MPA-10), Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

Large single crystals from RENi{sub 2-x}P{sub 2} (RE=La, Ce, Pr) were synthesized from the pure elements using Sn as a metal flux, and their structures were established by X-ray crystallography. The title compounds were confirmed to crystallize in the body-centered tetragonal ThCr{sub 2}Si{sub 2} structure type (space group I4/mmm (No. 139); Pearson's symbol tI10), but with a significant homogeneity range with respect to the transition metal. Systematic synthetic work, coupled with accurate structure refinements indicated strong correlation between the degree of Ni-deficiency and the reaction conditions. According to the temperature dependent dc magnetization measurements, LaNi{sub 2-x}P{sub 2} (x=0.30(1)), as expected, is Pauli-like paramagnetic in the studied temperature regime, while the Ce-analog CeNi{sub 2-x}P{sub 2} (x=0.28(1)) shows the characteristics of a mixed valent Ce{sup 3+}/Ce{sup 4+} system with a possible Kondo temperature scale on the order of 1000 K. For three different PrNi{sub 2-x}P{sub 2} (x<=0.5) samples, the temperature and field dependence of the magnetization indicated typical local moment 4f-magnetism and a stable Pr{sup 3+} ground state, with subtle variations of T{sub C} as a function of the concentration of Ni defects. Field-dependent heat capacity data for CeNi{sub 2-x}P{sub 2} (x=0.28(1)) and PrNi{sub 2-x}P{sub 2} (x=0.53(1)) are discussed as well. - Graphical abstract: The non-stoichiometric RENi{sub 2-x}P{sub 2} phases (RE=La, Ce, Pr), whose average structure belongs to the ThCr{sub 2}Si{sub 2} type, are shown to exist with a wide range of defects on the transition metal site. The changes in the Ni-underoccupancy affect the magnetism of the synthesized materials.

• OSTI ID: 21370438
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 6 Vol. 182; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CERIUM COMPOUNDS
CERIUM IONS
CERIUM PHOSPHIDES
CHARGED PARTICLES
COHERENT SCATTERING
CRYSTAL DEFECTS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CRYSTALLOGRAPHY
CRYSTALS
DIFFRACTION
ELECTROMAGNETIC RADIATION
ENERGY LEVELS
GROUND STATES
IONIZING RADIATIONS
IONS
LANTHANUM COMPOUNDS
LANTHANUM PHOSPHIDES
MAGNETISM
MAGNETIZATION
MONOCRYSTALS
NICKEL COMPOUNDS
NICKEL PHOSPHIDES
PARAMAGNETISM
PHOSPHIDES
PHOSPHORUS COMPOUNDS
PHYSICAL PROPERTIES
PNICTIDES
PRASEODYMIUM COMPOUNDS
PRASEODYMIUM IONS
PRASEODYMIUM PHOSPHIDES
RADIATIONS
RARE EARTH COMPOUNDS
SCATTERING
SPACE GROUPS
SPECIFIC HEAT
SYMMETRY GROUPS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE
TEMPERATURE RANGE 0400-1000 K
TETRAGONAL LATTICES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
X RADIATION
X-RAY DIFFRACTION