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arXiv · 1606.09416

Quantum phase transitions and multicriticality in Ta(Fe1-xVx)2

Manuel Brando·Alexander Kerkau·Adriana Todorova·Yoshihiro Yamada·Panchanan Khuntia·Tobias Foerster·Ulrich Burkhardt·Michael Baenitz·Guido Kreiner
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Abstract

We present a comprehensive study of synthesis, structure analysis, transport and thermodynamic properties of the C14 Laves phase Ta(Fe1-xVx)2. Our measurements confirm the appearance of spin-density wave (SDW) order within a dome-like region of the x - T phase diagram with vanadium content 0.02 < x < 0.3. Our results indicate that on approaching TaFe2 from the vanadium-rich side, ferromagnetic (FM) correlations increase faster than the antiferromagnetic (AFM) ones. This results in an exchange-enhanced susceptibility and in the suppression of the SDW transition temperature for x < 0.13 forming the dome-like shape of the phase diagram. This effect is strictly related to a significant lattice distortion of the crystal structure manifested in the c/a ratio. At x = 0.02 both FM and AFM energy scales have similar strength and the system remains paramagnetic down to 2 K with an extremely large Stoner enhancement factor of about 400. Here, spin fluctuations dominate the temperature dependence of the resistivity \rho ~ T ^ 3/2 and of the specific heat C/T ~ - log(T) which deviate from their conventional Fermi liquid forms, inferring the presence of a quantum critical point of dual nature.

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Manuel Brando, Alexander Kerkau, Adriana Todorova, Yoshihiro Yamada, Panchanan Khuntia, Tobias Foerster, Ulrich Burkhardt, Michael Baenitz, Guido Kreiner. 2016-06-30. Quantum phase transitions and multicriticality in Ta(Fe1-xVx)2. https://doi.org/10.7566/jpsj.85.084707

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