Mixed magnetic phase in Co-rich metallic glasses

Journal Article · Fri Nov 15 04:00:00 EST 1991 · Journal of Applied Physics; (United States)

DOI:https://doi.org/10.1063/1.349982· OSTI ID:5156535

Das, A; Majumdar, A K ^[1]

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1. Department of Physics, Indian Institute of Technology, Kanpur 208 016 (India)

ac susceptibility ({chi}) and magnetoresistance (MR) have been measured in Co-rich amorphous ferromagnets (Fe{sub 5}Co{sub 50}Ni{sub 17{minus}{ital x}}Cr{sub {ital x}}(BSi){sub 28} ({ital x}=0,5,10,15), Fe{sub 5}Co{sub 50}Mn{sub 17}(BSi){sub 28}, and Fe{sub 7.8}Co{sub 31.2}Ni{sub 24}Mn{sub 15}(BSi){sub 22}) to understand the changes in magnetic phase brought by the addition of Cr/Mn. The {ital T}{sub {ital c}} decreases monotonically with Cr/Mn addition. Samples with {ital x}=0--15 remain ferromagnetic down to 16 K. But for the Mn substituted samples below 80 K, {chi} decreases drastically and at 16 K it is only 5% of its value at 80 K indicating spin freezing. dc magnetization data show a peak around 30 K as well as a time dependence in the Mn{sub 17} sample. Presence of significant ferromagnetic anisotropy of resistance (FAR) even at the lowest temperature for both Mn-containing samples indicates that ferromagnetism persists even when transverse spin freezing is present. With lowering of temperature FAR increases, and below 30 K it should have decreased considerably if the lowest temperature phase was purely spin-glass-like but here it remains almost constant. The high-field slopes for {ital T} {lt} {ital T}{sub {ital c}} in both orientations are negative. In particular, for Mn{sub 15} sample the slope has a broad maximum decreasing on both sides as {ital T} {r arrow} {ital T}{sub {ital c}} and {ital T}{lt}80 K. This behavior is interpreted in terms of a transverse spin freezing. We conclude that the lowest temperature ({lt}30 K) phase in samples containing Mn is a mixture of spin-glass and long-range ferromagnetism. Samples containing Cr show a large positive slope for {ital T} {lt} {ital T}{sub {ital c}} and a very low FAR.

• OSTI ID: 5156535
• Journal Information: Journal of Applied Physics; (United States), Journal Name: Journal of Applied Physics; (United States) Vol. 70:10; ISSN 0021-8979; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360204 -- Ceramics
Cermets
& Refractories-- Physical Properties
ALLOYS
AMORPHOUS STATE
BORON ALLOYS
CHROMIUM ALLOYS
COBALT ALLOYS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
IRON ALLOYS
MAGNETIC PROPERTIES
MAGNETIC SUSCEPTIBILITY
MAGNETORESISTANCE
MANGANESE ALLOYS
NICKEL ALLOYS
PHYSICAL PROPERTIES
SILICON ALLOYS
SPIN GLASS STATE