Magnetic behavior in Mg-stabilized bcc. beta. -Gd and. beta. -Dy

Journal Article · Thu Jun 01 04:00:00 EDT 1989 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.39.11850· OSTI ID:6194669

Herchenroeder, J W

bcc ..beta..-Gd and ..beta..-Dy, stabilized by Mg additions, exhibit spin-glass-like behavior. Both systems show field-cooling effects in the magnetic susceptibility which is indicative of spin freezing reactions. The ..beta..-Gd alloys order ferromagnetically (/lt/80 K) first on cooling before undergoing a Gabay-Toulouse-type reentrant spin-glass transition (/lt/50 K) into a mixed ferromagnetic plus spin-glass phase. Low-field ac susceptibility measurements show both the Curie and spin freezing transitions. Low-temperature heat capacity (down to 1.5 K) shows evidence of both ferromagnetic and spin-glass excitations. A magnetic phase diagram predicts a pure spin-glass phase for Gd concentrations up to 66 at. % Gd. The ..beta..-Dy alloys exhibit a cusp in the ac susceptibility characteristic of spin-glass behavior. Field-cooled magnetic-susceptibility measurements suggest a close competition between antiferromagnetism and spin-glass behavior. The occurrence of the maximum in the magnetic susceptibility at 1.4 T is evidence that some atoms may order antiferromagnetically. A large linear heat-capacity term which is probably due to both the electronic specific heat ..gamma.. and a spin-glass contribution plus the presence of large /ital T//sup 2/ and /ital T//sup 3/ terms support the mixed-state hypothesis. The metastable bcc Gd-Mg and Dy-Mg alloys are unique in that they have the highest concentration of magnetic atoms in a /ital crystalline/, /ital metallic/ spin glass (/gt/70 at. % Gd or Dy).

• Research Organization: Ames Laboratory and Department of Materials Science and Engineering, Iowa State University, Ames, Iowa 50011(US)
• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 6194669
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 39:16; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
ALLOYS
ANTIFERROMAGNETISM
BCC LATTICES
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CUBIC LATTICES
DYSPROSIUM
ELEMENTS
FERROMAGNETISM
GADOLINIUM
LOW TEMPERATURE
MAGNESIUM ADDITIONS
MAGNESIUM ALLOYS
MAGNETIC PROPERTIES
MAGNETIC SUSCEPTIBILITY
MAGNETISM
METALS
PHYSICAL PROPERTIES
RARE EARTHS
SPECIFIC HEAT
SPIN GLASS STATE
THERMODYNAMIC PROPERTIES
ULTRALOW TEMPERATURE
VERY LOW TEMPERATURE