Spin dynamics of amorphous Fe sub 90 minus x Ni sub x Zr sub 10 (invited)

Journal Article · Tue May 01 04:00:00 EDT 1990 · Journal of Applied Physics; (USA)

DOI:https://doi.org/10.1063/1.344618· OSTI ID:6838028

Fernandez-Baca, J A ^[1]; Rhyne, J J ^[2]; Fish, G E ^[3]; Hennion, M; Hennion, B ^[4]

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1. Solid State Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6393 (USA)
2. National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (USA)
3. Allied Signal, Inc., Morristown, New Jersey 07962 (USA)
4. Laboratoire Leon Brillouin, CEN-Saclay, 91191 Gif sur Yvette Cedex (France)

Amorphous Fe{sub 90{minus}{ital x}}Ni{sub {ital x}}Zr{sub 10} is a system that exhibits a relatively high degree of magnetic exchange frustration, which becomes stronger as the system approaches the composition of amorphous pure iron. Thus, while samples with moderate amounts of iron ({ital x}{ge}5) are ferromagnetic, the samples with the highest concentration of iron ({ital x}{le}1) behave like reentrant spin glasses. We have performed a detailed neutron scattering study of the spin-wave excitations in this system for {ital x}=1, 5, 10, 20. In all cases, well-defined spin-wave excitations were observed below a transition temperature {ital T}{sub {ital c}} that decreased from 455 K (for {ital x}=20) to 250 K (for {ital x}=1). For {ital x}=5, 10, 20 the spin-wave stiffness coefficient follows the temperature dependence expected for a conventional ferromagnet but the spin-wave excitations broaden considerably at low temperatures. For {ital x}=1 the spin-wave stiffness coefficient softens at low temperatures and an elastic component of the scattering, associated with the development of a spin-glass order parameter, appears below {ital T}{approx}0.28{ital T}{sub {ital c}}. A coexistence of propagating spin-wave excitations and spin freezing phenomena is observed below this temperature down to {ital T}=0.09{ital T}{sub {ital c}}. These results are discussed in terms of the relevant current theories.

• DOE Contract Number: AC05-84OR21400
• OSTI ID: 6838028
• Journal Information: Journal of Applied Physics; (USA), Journal Name: Journal of Applied Physics; (USA) Vol. 67:9; ISSN 0021-8979; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
ALLOYS
AMORPHOUS STATE
COHERENT SCATTERING
DIFFRACTION
HIGH TEMPERATURE
IRON ALLOYS
LOW TEMPERATURE
MEDIUM TEMPERATURE
NEUTRON DIFFRACTION
NICKEL ALLOYS
ORDER PARAMETERS
SCATTERING
SPIN GLASS STATE
SPIN WAVES
ZIRCONIUM ALLOYS