V. O. Garlea

Publications (3)7.38 Total impact

• Source

  Available from: I. A. Zaliznyak

  Article: Continuous magnetic and structural phase transitions in Fe1+yTe

  I. A. Zaliznyak, Z. J. Xu, J. S. Wen, J. M. Tranquada, G. D. Gu, V. Solovyov, V. N. Glazkov, A. I. Zheludev, V. O. Garlea, M. B. Stone
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  ABSTRACT: We report a sequence of continuous phase transformations in iron telluride, Fe1+yTe (y~0.1), which is observed by combining neutron diffraction, magnetic susceptibility, and specific heat measurements on single crystal samples. While a gradual increase of magnetic scattering near the wave vector (0.5, 0, 0.5) is seen below T = 70 K, a temperature where the discontinuous first order magneto-structural phase transition is found in systems with small y (< 0.06), the reduction of the lattice symmetry in Fe1.1Te only occurs at Ts = 63 K. Below TN = 57.5 K the long-range magnetic order develops, whose incommensurate wave vector Qm varies with temperature. Finally, at Tm ~ 45 K the system enters the low-T phase, where Qm is locked at (0.48, 0, 0.5). We conclude that these instabilities are weak compared to the strength of the underlying interactions, and we suggest that the impact of the Fe interstitials on the transitions can be treated with random-field models.
  Physical Review B 02/2012; 85:085105. · 3.69 Impact Factor
• Source

  Available from: I. A. Zaliznyak

  Article: Absence of localized-spin magnetism in the narrow-gap semiconductor FeSb2

  I. A. Zaliznyak, A. T. Savici, V. O. Garlea, Rongwei Hu, C. Petrovic
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  ABSTRACT: We report on the inelastic neutron scattering measurements aimed at investigating the origin of temperature-induced paramagnetism in narrow-gap semiconductor FeSb2. We find that inelastic response for energies up to 60 meV and at temperatures ≈4.2, ≈300, and ≈550 K is essentially consistent with the scattering by lattice phonon excitations. We observe no evidence for a well-defined magnetic peak corresponding to the excitation from the nonmagnetic S=0 singlet ground state to a state of magnetic multiplet in the localized-spin picture. Our data establish the quantitative limit of Seff2≲0.25 on the fluctuating local spin. However, a broad magnetic scattering continuum in the 15 to 35 meV energy range is not ruled out by our data. Our findings make description in terms of the localized Fe spins unlikely and suggest that paramagnetic susceptibility of itinerant electrons is at the origin of the temperature-induced magnetism in FeSb2.
  Physical Review B 05/2011; 83:184414. · 3.69 Impact Factor
• Article: Continuous magnetic and structural phase transitions in Fe_ {1+ y} Te

  I. A. Zaliznyak, Z. J. Xu, J. S. Wen, J. M. Tranquada, G. D. Gu, V. Solovyov, V. N. Glazkov, A. I. Zheludev, V. O. Garlea, M. B. Stone
  [show abstract] [hide abstract]
  ABSTRACT: We report a sequence of continuous phase transformations in iron telluride, Fe1+yTe with y=0.10(1), which is observed by combining neutron diffraction, magnetic susceptibility, and specific-heat measurements on single-crystal samples. While a gradual increase of magnetic scattering near the wave vector (0.5,0,0.5) is seen below T≈70 K, a temperature where the discontinuous first-order magnetostructural phase transition is found in systems with small y (≲0.06), the reduction of the lattice symmetry in Fe1.1Te only occurs at Ts≈63 K. Below TN≈57.5 K, the long-range magnetic order develops, the incommensurate wave vector Qm of which varies with temperature. Finally, at Tm≲45 K, the system enters the low-T phase, where Qm is locked at ≈(0.48,0,0.5). We conclude that these instabilities are weak compared to the strength of the underlying interactions, and we suggest that the impact of the Fe interstitials on the transitions can be treated with random-field models.
  Phys. Rev. B. 85(8).