2019/02/13 by M. Yokoyama, K. Suzuki, Kohei Suzuki +10
Materials Science · Mathematics · Physics and Astronomy · #Anisotropy #Condensed matter physics #Critical field #Fermi liquid theory #Field (mathematics) #Ising model #Magnetic and transport properties of perovskites and related materials #Mathematics #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Rare-earth and actinide compounds #Spin (aerodynamics) #Superconductivity #Thermodynamics #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.99.054506
published as Phys. Rev. B 99, 054506 (2019) · 7 pages, 5 figures, to appear in Phys. Rev. B
arxiv created 2019/02/13 · openalex publication_date 2019/02/14 · arxiv updated 2019/02/19 · openalex created_date 2019/02/21 · openalex updated_date 2026/08/05
This paper demonstrates the anisotropic response of quantum critical fluctuations with respect to the direction of the magnetic field B in Ni-doped CeCoIn5 by measuring the magnetization M and specific heat C. The results show that M/B at B=0.1\phantom\rule4pt0exT for both the tetragonal c and a directions exhibits T^\ensuremath-\ensuremathη dependencies, and that C/T at B=0 follows a \ensuremath-lnT function, which are the characteristics of non-Fermi-liquid (NFL) behaviors. For B\phantom\rule0.16em0ex||\phantom\rule0.16em0exc, both the M/B\ensuremath∝T^\ensuremath-\ensuremathη and C/T\ensuremath∝\ensuremath-lnT dependencies change into nearly temperature-constant behaviors by increasing B, indicating a crossover from the NFL state to the Fermi-liquid state. For B\phantom\rule0.16em0ex||\phantom\rule0.16em0exa, however, the NFL behavior in C/T persists up to B=7\phantom\rule4pt0exT, whereas M/B exhibits temperature-independent behavior for B\ensuremath≥1\phantom\rule4pt0exT. These contrasting characteristics in M/B and C/T reflect the anisotropic nature of quantum critical fluctuations; the c-axis spin component significantly contributes to the quantum critical fluctuations. We compare this anisotropic behavior of the spin fluctuations to superconducting properties in pure CeCoIn5, especially to the anisotropy in the upper critical field and the Ising-like characteristics in the spin resonance excitation, and suggest a close relationship between them.