Magnetic order in nanocrystalline Cr and suppression of antiferromagnetism in bcc Cr

Journal Article · Wed Sep 15 00:00:00 EDT 1993 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.48.8245· OSTI ID:6255539

Fitzsimmons, M R ^[1]; Eastman, J A ^[2]; Robinson, R A; Lawson, A C; Thompson, J D; Movshovich, R ^[1]; Satti, J ^[2]

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1. Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
2. Argonne National Laboratory, Argonne, Illinois 60439 (United States)

Neutron-diffraction data and magnetization measurements of compacted nanophase Cr are presented. Two crystalline Cr phases were found, the majority phase having a bcc structure and the minority phase having an [ital A]15 structure. The 100 Bragg reflection seen in antiferromagnetically ordered coarse-grained bcc-Cr polycrystals was not observed in the nanocrystalline sample, suggesting that antiferromagnetism was suppressed in the bcc phase to at least 20 K. The suppression of antiferromagnetism may be due to small grain sizes, strain from grain boundaries or other defects, and/or concentrations of impurities, any of which may restrict the development of magnetic correlations in the bcc material. A magnetic diffraction peak corresponding to the 110 Bragg reflection of the Cr [ital A]15 lattice was observed at 20 K and was not observed at 149 or 300 K, suggesting that the minority phase of the nanocrystalline sample becomes antiferromagnetically ordered at very low temperatures. Consistent with this observation, susceptibility measurements at several temperatures indicate that magnetic correlations develop below 100 K, representing at least momentary short-ranged magnetic order in the nanocrystalline sample.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL
• DOE Contract Number: W-31109-ENG-38; W-7405-ENG-36
• OSTI ID: 6255539
• Journal Information: Physical Review, B: Condensed Matter; (United States), Vol. 48:11; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHROMIUM
MAGNETIC PROPERTIES
ANTIFERROMAGNETISM
BCC LATTICES
BRAGG REFLECTION
GRAIN SIZE
MAGNETIZATION
NEUTRON DIFFRACTION
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K
COHERENT SCATTERING
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CUBIC LATTICES
DIFFRACTION
ELEMENTS
MAGNETISM
METALS
MICROSTRUCTURE
PHYSICAL PROPERTIES
REFLECTION
SCATTERING
SIZE
TEMPERATURE RANGE
TRANSITION ELEMENTS
360104* - Metals & Alloys- Physical Properties