Critical exponents of amorphous Gd/sub 0. 70/Pd/sub 0. 30/

Journal Article · Tue Jan 01 04:00:00 EST 1985 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.31.287· OSTI ID:6222780

Griffiths, D J; Easton, D S; Kroeger, D M

The magnetization of liquid-quenched amorphous Gd/sub 0.70/Pd/sub 0.30/ was measured between temperatures of 77 and 300 K in fields up to 6 kOe. The ferromagnetic Curie temperature T/sub C/ and the critical exponents ..beta.., ..gamma.., and delta were found to be 131.77 +- 0.20 K, 0.34 +- 0.02, 1.010 +- 0.003, and 3.95 +- 0.10, respectively. These experimentally determined values of the critical exponents very clearly satisfy the scaling law ..gamma.. = ..beta..(delta-1). Of special interest is the value of unity for ..gamma.. in the neighborhood of the ferromagnetic Curie temperature, the usual Curie-Weiss plot of inverse susceptibility yielding a paramagnetic Curie temperature of 155.20 +- 0.20 K. EPR measurements made over the temperature range of 135 to 100 K reveal an almost-free Gd/sup 3 +/-ion response broadened and made asymmetric by conduction-electron effects, while at the same time exhibiting no significant directional dependence on the applied field. This result and the lack of hysteresis at 77 K support the idea that liquid-quenched Gd/sub 0.70/Pd/sub 0.30/ becomes an isotropic amorphous ferromagnet at T/sub C/. Finally, examination of sections of a given sample (produced via the hammer-and-anvil technique) reveal that, even at the highest cooling rates (approx.10/sup 7/ K s/sup -1/), entirely amorphous material may be produced only toward the sample edges, in agreement with current models of amorphous cooling in liquid-quenched samples.

• Research Organization: Department of Physics, Oregon State University, Corvallis, Oregon 97331
• OSTI ID: 6222780
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 31:1; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
ALLOYS
AMORPHOUS STATE
COHERENT SCATTERING
CURIE POINT
DATA
DIAGRAMS
DIFFRACTION
ELECTRON SPIN RESONANCE
EXPERIMENTAL DATA
FERROMAGNETISM
FOILS
GADOLINIUM ALLOYS
INFORMATION
LINE BROADENING
LOW TEMPERATURE
MAGNETIC FIELDS
MAGNETIC RESONANCE
MAGNETISM
MAGNETIZATION
MEDIUM TEMPERATURE
NUMERICAL DATA
PALLADIUM ALLOYS
PHASE DIAGRAMS
PHYSICAL PROPERTIES
PLATINUM METAL ALLOYS
QUENCHING
RARE EARTH ALLOYS
RESONANCE
SCALING LAWS
SCATTERING
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE
X-RAY DIFFRACTION