Thermal and Magnetic Properties in Ce_1−xEr_xAl₂ Intermetallic Compounds

Abstract

The magnetic and thermal properties of Ce 1−x Er x Al 2 compounds have been studied using specific heat, dc magnetization, and ac susceptibility measurements. All these compounds are isomorphic with the MgCu 2 Laves phase, and the lattice parameter decreases almost linearly with the increasing Er concentration x. The dc magnetic susceptibility follows the Curie-Weiss law, and the Weiss temperature continuously changes from Θ = −24 K for x = 0 to Θ = 15 K for x = 1, indicating a change from antiferro-magnetism to ferromagnetism.Θ changes from negative to positive at around x = 0.2 where where a field-induced metamagnetic transition disappears. The magnetic ordering state continuously changes with the change in x from antiferromagnetc to ferromagnetic through a spin-glass-like behavior.

New bridge-circuit-type detector to measure precise resistance change of strain gauge at low temperature and magnetic field

“…12,13) In most of these compounds, the R ions are trivalent (3+) and a ferromagnetic ordering caused by local magnetic moments of R ions has been observed with Curie temperatures (T C ) of up to 170 K. 3,8,9,12) It is expected that some of the structural transition occurs owing to magnetic symmetry breaking below T C .…”

“…To demonstrate the use of the new detector in strain measurements, we measured the thermal expansion and magnetostriction of RAl 2 (R: rare earth element) single crystals that crystallize in the MgCu 2 cubic Laves phase structure (Fd " 3m, space group 227). 12,13) In most of these compounds, the R ions are trivalent (3+) and a ferromagnetic ordering caused by local magnetic moments of R ions has been observed with Curie temperatures (T C ) of up to 170 K. 3,8,9,12) It is expected that some of the structural transition occurs owing to magnetic symmetry breaking below T C .…”

“…On the other hand, it is well known that a commercial physical property measurement system (PPMS; Quantum Design) is a useful apparatus for the generation of extreme conditions and has been used in our previous measurements of physical properties such as electrical resistance and heat capacity for a variety of materials. [8][9][10][11] In this paper, we describe a new bridge-circuit-type detector to detect extremely small resistance changes in thermal expansion and magnetostriction measurements using the PPMS.…”