Resistivity and thermopower of Ho(Co1-xAlx) 2-effects of pressure and magnetic field

Kiyoharu Uchima, Chojun Zukeran, Ai Nakamura, Nozomi Arakaki, Shota Komesu, Masataka Takeda, Yoshinao Takaesu, Heinz Georg Flesch, Masato Hedo, Takao Nakama, Katsuma Yagasaki, Alexander T. Burkov

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

The electrical resistivity ρ and thermopower S of the cubic Laves phase compounds Ho(Co1-xAlx)2 (x = 0, 0.15 and 0.20) have been measured at temperatures from 2 K to 300 K in magnetic fields up to 10 T. The measurements of ρ under pressures up to 3 GPa have been performed in the temperature range between 2 K and 300 K. Both ρ(T) and S(T) of the pure HoCo2 reveal abrupt changes at the magnetic ordering temperature TC, indicating the first order transition. ρ(T) of the Al substituted samples (x = 0.15 and 0.20) show anomalous behavior in the form of an increase below TC. The variations of ρ and S at TC clearly indicate that the type of the magnetic transition changes under substitution of Al for Co from the first order to the second order. The residual resistivity of Ho(Co1-xAlx)2 shows a rapid increase with increasing x. TC increases linearly for x < 0.15, having a maximum at x ≈ 0.15 and decreases with further increase of x. The peculiar x dependence of TC and the anomalous behavior of ρ(T) and S (T) around TC are related to the metamagnetic instability of Co 3d subsystem and to fluctuating local magnetic susceptibility due to the atomic substitution.

Original languageEnglish
Article numberSA086
Journaljournal of the physical society of japan
Volume80
Issue numberSUPPL. A
DOIs
Publication statusPublished - 2011 Jul 1
Externally publishedYes

Keywords

  • Electrical resistivity
  • Magnetic field
  • Pressure effect
  • Thermopower

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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