From superconductivity to ferromagnetism in amorphous Gd--La--Au alloys. [(La/sub 100-x/Gd/sub x/)/sub 80/Au/sub 20/, x = 0 to 100, 1. 7 to 300/sup 0/K]

Technical Report · Sun Aug 01 04:00:00 EDT 1976

DOI:https://doi.org/10.2172/7144061· OSTI ID:7144061

Poon, S. J.; Durand, J.

Splat-cooled alloys of composition (La/sub 100-x/Gd/sub x/)/sub 80/Au/sub 20/ have been obtained by complete substitution of gadolinium for lanthanum in amorphous La/sub 80/Au/sub 20/ matrix. Results of high-field magnetization (up to 70 kOe), ac and dc low-field susceptibility, and resistivity measurements over temperature range of 1.7 to 300/sup 0/K for these alloys are reported. The La/sub 90/Au/sub 20/ alloys are superconducting at 3.5/sup 0/K. For x approximately less than 1, a suppression of T/sub c/ described by the relation dT/sub c//dx approximately equal to -4.0/sup 0/K per atomic per cent gadolinium is observed. For alloys within the concentration range 1 approximately less than x approximately less than 70, maxima in low field susceptibility measurements are observed. The ''ordering'' temperature, T/sub M/, are proportional to x for 1 less than or equal to x less than or equal to 16, similar to those observed in crystalline spin-glass alloys. For 16 approximately less than x approximately less than 70, T/sub M/ is increasing at a faster rate than in the low concentration region, and this intermediate type of ordering corresponds to a mictomagnetic regime. At x approximately greater than 70, a ferromagnetic regime emerges. The maximum Curie temperature is observed for Gd/sub 80/Au/sub 20/ at approximately 150/sup 0/K. The moment per gadolinium atom is found to be constant and close to that of the crystalline value throughout the concentration range investigated. Results of resistivity measurements are correlated with the magnetic properties of different regimes in the magnetic phase diagram. 4 figures, 1 table.

• Research Organization: California Inst. of Tech., Pasadena (USA). W.M. Keck Lab. of Engineering Materials
• OSTI ID: 7144061
• Report Number(s): CALT-822-86
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
656102 -- Solid State Physics-- Superconductivity-- Acoustic
Electronic
Magnetic
Optical
& Thermal Phenomena-- (-1987)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALLOY SYSTEMS
ALLOYS
ANTIFERROMAGNETISM
BINARY ALLOY SYSTEMS
CURIE POINT
DIAGRAMS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
FERROMAGNETISM
GADOLINIUM ALLOYS
GADOLINIUM BASE ALLOYS
GOLD ALLOYS
LANTHANUM ALLOYS
LANTHANUM BASE ALLOYS
LOW TEMPERATURE
MAGNETIC MOMENTS
MAGNETIC PROPERTIES
MAGNETIC SUSCEPTIBILITY
MAGNETISM
MAGNETIZATION
MEDIUM TEMPERATURE
MICTOMAGNETISM
PHASE DIAGRAMS
PHYSICAL PROPERTIES
RARE EARTH ALLOYS
SUPERCONDUCTIVITY
TERNARY ALLOY SYSTEMS
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE
ULTRALOW TEMPERATURE
VERY LOW TEMPERATURE