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Title: Nickel deficiency in RENi2-xP2 (RE=La, Ce, Pr). Combined crystallographic and physical property studies

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 stoichiometry breadth 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. For four different PrNi{sub 2-x}P{sub 2} (x {le} 0.5) samples, temperature dependent dc magnetization measurements indicated typical local moment 4f-magnetism and a stable Pr{sup 3+} ground state. Field-dependent heat capacity data confirmed a ferromagnetic order at low temperature, and the variations of T{sub c} with the concentration of Ni defects are discussed. LaNi{sub 2-x}P{sub 2}, as expected was found to be Pauli-like paramagnetic in the studied temperature regime, while the Ce-analog CeNi{sub 2-x}P{sub 2} (x = 0.28(1)) showed the characteristics of a mixed valent Ce{sup 3+}/Ce{sup 4+} system with a possible Kondo temperature on the order of 230 K.
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [2]
  1. Los Alamos National Laboratory
  2. U. OF DE
Publication Date:
OSTI Identifier:
962290
Report Number(s):
LA-UR-08-07752; LA-UR-08-7752
Journal ID: ISSN 0022-4596; JSSCBI; TRN: US200919%%54
DOE Contract Number:
AC52-06NA25396
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry
Research Org:
Los Alamos National Laboratory (LANL)
Sponsoring Org:
DOE
Country of Publication:
United States
Language:
English
Subject:
36; CRYSTALLOGRAPHY; DEFECTS; GROUND STATES; MAGNETIZATION; MONOCRYSTALS; NICKEL; SPECIFIC HEAT; STOICHIOMETRY; TRANSITION ELEMENTS