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Structural, electronic, magnetic, and thermal properties of single-crystalline UNi0.5Sb2
Authors:
M. S. Torikachvili,
B. K. Davis,
K. Kothapalli,
H. Nakotte,
A. J. Schultz,
E. D. Mun,
S. L. Bud'ko
Abstract:
We studied the properties of the antiferromagnetic (AFM) UNi0.5Sb2 (TN \approx 161 K) compound in Sb-flux grown single crystals by means of measurements of neutron diffraction, magnetic susceptibility (χ), specific heat (Cp), thermopower (S), thermal conductivity (κ), linear thermal expansion (ΔL/L), and electrical resistivity (ρ) under hydrostatic pressures (P) up to 22 kbar. The neutron diffract…
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We studied the properties of the antiferromagnetic (AFM) UNi0.5Sb2 (TN \approx 161 K) compound in Sb-flux grown single crystals by means of measurements of neutron diffraction, magnetic susceptibility (χ), specific heat (Cp), thermopower (S), thermal conductivity (κ), linear thermal expansion (ΔL/L), and electrical resistivity (ρ) under hydrostatic pressures (P) up to 22 kbar. The neutron diffraction measurements revealed that the compound crystallizes in the tetragonal P42/nmc structure, and the value of the U-moments yielded by the histograms at 25 K is \approx 1.85 \pm 0.12 μB/U-ion. In addition to the features in the bulk properties observed at TN, two other hysteretic features centered near 40 and 85 K were observed in the measurements of χ, S, ρ, and ΔL/L. Hydrostatic pressure was found to raise TN at the rate of \approx 0.76 K/kbar, while suppressing the two low temperature features. These features are discussed in the context of Fermi surface and hybridization effects.
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Submitted 11 October, 2011; v1 submitted 21 May, 2011;
originally announced May 2011.
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Hydrostatic pressure effects on the electrical transport properties of Pr0.5Sr0.5MnO3
Authors:
F. J. Rueckert,
M. Steiger,
B. K. Davis,
T. Huynh,
J. J. Neumeier,
M. S. Torikachvili
Abstract:
We studied single-crystalline Pr0.5Sr0.5MnO3 by means of measurements of magnetic susceptibility and specific heat at ambient pressure (P), and electrical resistivity (r) in hydrostatic pressures up to 2 GPa. This material displays ferromagnetic (FM) order, with Curie temperature TC ~ 255 K. A crystallographic transformation from I4/mcm to Fmmm is accompanied by the onset of antiferromagnetism (…
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We studied single-crystalline Pr0.5Sr0.5MnO3 by means of measurements of magnetic susceptibility and specific heat at ambient pressure (P), and electrical resistivity (r) in hydrostatic pressures up to 2 GPa. This material displays ferromagnetic (FM) order, with Curie temperature TC ~ 255 K. A crystallographic transformation from I4/mcm to Fmmm is accompanied by the onset of antiferromagnetism (AFM), with Neel temperature TN ~ 161 K. The effect of pressure is to lower TC, and raise TN at the approximate rates of -3.2 K/GPa, and 14.2 K/GPa, respectively. Although the value of TN increases with P, due to the enhancement of the superexchange interactions, the AFM-Fmmm state is progressively suppressed, as pressure stabilizes the FM-I4/mcm phase to lower temperatures. The r vs T data suggest that the AFM phase should be completely suppressed near 2.4 GPa.
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Submitted 29 September, 2007;
originally announced October 2007.
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Hydrostatic pressure study of single-crystalline UNi0.5Sb2
Authors:
B. K. Davis,
M. S. Torikachvili,
E. D. Mun,
J. C. Frederick,
G. J. Miller,
S. Thimmaiah,
S. L. Budko,
P. C. Canfield
Abstract:
We studied single-crystals of the antiferromagnetic compound UNi0.5Sb2 (TN ~ 161 K) by means of measurements of magnetic susceptibility (chi), specific heat (Cp), and electrical resistivity (rho) at ambient pressure, and resistivity under hydrostatic pressures up to 20 kbar, in the temperature range from 1.9 to 300 K. The thermal coefficient of the electrical resistivity (drho/dT) changes drasti…
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We studied single-crystals of the antiferromagnetic compound UNi0.5Sb2 (TN ~ 161 K) by means of measurements of magnetic susceptibility (chi), specific heat (Cp), and electrical resistivity (rho) at ambient pressure, and resistivity under hydrostatic pressures up to 20 kbar, in the temperature range from 1.9 to 300 K. The thermal coefficient of the electrical resistivity (drho/dT) changes drastically from positive below TN to negative above, reflecting the loss of spin-disorder scattering in the ordered phase. Two small features in the rho vs T data centered near 40 and 85 K correlate well in temperature with features in the magnetic susceptibility and are consistent with other data in the literature. These features are quite hysteretic in temperature, i.e., the difference between the warming and cooling cycles are about 10 and 6 K, respectively. The effect of pressure is to raise TN at the approximate rate of 0.76 K/kbar, while progressively suppressing the amplitude of the small features in rho vs T at lower temperatures and increasing the thermal hysteresis.
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Submitted 29 September, 2007;
originally announced October 2007.