Magnetostriction of rare-earth random magnetic anisotropy spin glasses

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

DOI:https://doi.org/10.1103/PhysRevB.39.9453· OSTI ID:6184276

del Moral, A; Arnaudas, J I

A model of magnetostriction for single-ion random magnetic anisotropy (RMA) spin glasses (SG) is developed, the calculation being based on the replica technique. An overall uniform strain is assumed and coupled to the local easy axis (or easy plane) by an adequate projection. The obtained bulk magnetostriction becomes proportional to the average quadrupolar moment, which depends upon the assumed ferromagnetic uniform exchange, J/sub 0/, and the RMA crystal field (CEF), D/sub 0/, strengths. Magnetostriction measurements parallel (lambda/sub X/) and perpendicular (lambda/sub perpendicular/) to the applied magnetic field (up to 7 T) have been performed between 4.2 and 150 K (much larger than the SG temperature, T/sub SG/) for the amorphous spin glasses R/sub 40/Y/sub 23/Cu/sub 37/ (R = Tb, Dy, Ho, and Er). Anisotropic magnetostriction is a forced effect, with no sign of saturation, and is quite large well above T/sub SG/. The developed model fits quantitatively and remarkably well the temperature variation of the anisotropic magnetostriction, lambda/sub t/ = lambda/sub X/-lambda/sub perpendicular/, in the case of Tb, Dy, and Ho alloys. The values obtained from the fit for D/sub 0/, respectively, are +3.0, +1.25, and +0.6 K. For Er, D/sub 0/ becomes -0.37 K. The signs of D/sub 0/ are in agreement with having local axial anisotropy for the Tb, Dy, and Ho compounds, and planar for the Er one, in good agreement with the signs of the ..cap alpha../sub J/ Stevens quadrupolar parameter.

• Research Organization: Laboratorio Magnetismo de Solidos, Instituto de Ciencia de Materiales de Aragon (ICMA) and Departamento de Fiiaasica de la Materia Condensada, Universidad de Zaragoza and Consejo Superior de Investigaciones Cientiiaaficas (CSIC), 50009-Zaragoza, Spain
• OSTI ID: 6184276
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 39:13; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
AMORPHOUS STATE
ANISOTROPY
COPPER COMPOUNDS
LOW TEMPERATURE
MAGNETIC PROPERTIES
MAGNETOSTRICTION
PHYSICAL PROPERTIES
RANDOMNESS
RARE EARTH COMPOUNDS
SPIN GLASS STATE
TEMPERATURE DEPENDENCE
TRANSITION ELEMENT COMPOUNDS
ULTRALOW TEMPERATURE
VERY LOW TEMPERATURE
YTTRIUM COMPOUNDS