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Long‐range and short‐range order in NiPt
Author(s) -
Greenholz M.,
Kidron A.,
Shimony U.
Publication year - 1974
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889874008752
Subject(s) - alloy , diffraction , phase (matter) , range (aeronautics) , condensed matter physics , intensity (physics) , order (exchange) , materials science , atmospheric temperature range , short range order , symmetry (geometry) , crystallography , thermodynamics , chemistry , physics , optics , mathematics , quantum mechanics , geometry , finance , economics , composite material
Experimental measurements were performed on a 48.4 at. % Ni/51.6 at. % Pt alloy. The order parameter S in equilibrium was measured as a function of temperature T by means of X‐ray diffraction. Up to 592±3°C the sample is a single‐phase ordered alloy with an order parameter above 0.98. Between 592 and 625±3°C there exists a two‐phase region in which the ordered and disordered phases are in equilibrium. Above 625±3°C a disordered f.c.c. structure exists. Diffuse X‐ray intensity measurements were performed at T = 1.1 T c and both the short‐range parameters α i and the size‐effect parameters β i were calculated. From the α i parameters so derived three ordering energies ν i were determined. It was found that these energies were consistent with the symmetry of the ordered phase below the critical temperature.