Evolution of a metallic and magnetic state in (Fe,Mn)Si and Fe(Si,Ge)

Bauer, Ernest; Galaţanu, A.; Hauser, Robert G.; Reichl, Christoph; Wiesinger, G.; Zaussinger, G.; Galli, Mattéo; Marabelli, F.

doi:10.1016/s0304-8853(97)00786-5

Cited by 18 publications

(13 citation statements)

References 8 publications

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“…For example, in FeSi with a large RR of 20 000 ⌬ decreases, in the 5% Ge sample with an intermediate RR of 1400 ⌬ decreases followed by an increase, and in the 20% Ge sample with RR of 247 ⌬ in- creases. Since we found a qualitatively different pressure dependence of ⌬ in pure FeSi from that of Bauer et al, 29 and our results indicate differences in the pressure dependence of ⌬ dictated by the RR, we found it worthwhile to investigate an FeSi sample with a poor RR of 7. This sample was Fe deficient ͑Feϭ49.9 at.…”

Section: Results: Pressure Dependence Of ⌬contrasting

confidence: 50%

“…25 In SmB 6 , 26 the gap decreases with pressure, whereas CeNiSn, 27 a KI with small gap, 28 metallizes with increase in pressure. In FeSi, Bauer et al 29 report from their resistivity measurements an increase in the value of ⌬ with external pressure; temperature dependent magnetic susceptibity measurements using a superconducting quantum interference device ͑SQUID͒ magnetometer reveal that ⌬ increases as a function of pressure. 30 In this paper we present the pressure dependence of the KI gap in samples with different Ge concentrations, which is known to alter the ⌬ values at ambient pressure.…”

Section: Introductionmentioning

confidence: 99%

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Pressure-induced insulator-metal transition of localized states inFeSi1−xGex

2001

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Resistivity measurements have been carried out in FeSi 1Ϫx Ge x (xϭ0.0, 0.05, and 0.20͒ in the 4-300 K range under the application of pressure up to 6.4 GPa. The resistivity data between 100 and 200 K fit an activated behavior yielding the measured transport gap ⌬. The trends in the pressure variation of ⌬ seems to depend on the measured resistivity ratio R(4.2 K)/R(300 K) at ambient pressure. The observed behavior of ⌬ with increase in pressure is argued to arise from two competing factors that contribute to ⌬, a decrease due to shift in the mobility edge E toward E F and an increase due to changes in the electronic structure of the bulk. A remarkable feature of the experimental results, however, is the drastic change in the temperature dependence of conductivity (T) in the 4-50 K range. In this temperature range, while (T) fits the variable range hopping transport mechanism in pristine FeSi, significant deviation from such a fit is seen with Ge substitution and under the application of pressure. The data in these cases fit better to power laws. A plot of the logarithmic derivative wϭd ln /d ln T as a function of T 1/2 for various external pressures reveals that w is a decreasing function of temperature for low pressure and gradually becomes an increasing function of temperature at higher pressures, in both FeSi and FeSi 0.95 Ge 0.05 . These results indicate that the localized states in the gap delocalize, giving rise to an insulator to metal transition as a function of pressure. From the nature of the temperature dependence of w across the transition, it can be surmised that the insulator to metal transition in FeSi is possibly continuous as in doped semiconductors.

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Section: Results: Pressure Dependence Of ⌬contrasting

confidence: 50%

Section: Introductionmentioning

confidence: 99%

Pressure-induced insulator-metal transition of localized states inFeSi1−xGex

2001

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“…In Fig. 3, one can see that the band gap decreases as a function of Ge concentration, in agreement with the experimental and theoretical results [5,7,25]. The differences of the band-gap widths for Fe 4 Si 4-x Ge x are attributed to the p state of Ge and Si, i.e.…”

Section: Density Of Statessupporting

confidence: 86%

Electronic structure of Fe₄Si_4–xGe_x (x = 0–4) compounds: ab initio calculation

Ameereh

Hamad

Khalifeh³

2008

Physica Status Solidi (b)

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The structural and electronic properties of Fe4Si4–x Gex (x = 0–4) with a cubic B20‐type structure are investigated by density functional theory using an ab initio method. The calculations are based on a plane‐wave expansion of the electronic wave functions and performed using the local density approximation. It is found that these compounds are narrow‐gap semiconductors in the non‐magnetic state. The band gap is found to decrease with increasing x, and the B20 FeSi is a small‐gap semiconductor with sharp density of states features near the top of the valence band. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Section: Introductionmentioning

confidence: 70%

“…Bauer et al showed that the energy gap of FeSi becomes narrower by substituting Ge for Si, and a metallic state evolves at x = 0.5 [17]. This is consistent with the increase of the gap size of FeSi under pressure [17,18], since alloying with Ge acts as a negative pressure on FeSi. Later, a local density approximation calculation suggested that a first-order phase transition from a nonmagnetic insulator to a ferromagnetic metal occurs in FeSi 1−x Ge x at around x = 0.4 [19].…”

Section: Introductionmentioning

confidence: 70%

Magnetic study of FeSi_1−xGe_xacross the nonmagnetic-ferromagnetic transition

Tsujii

2017

J. Phys.: Conf. Ser.

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Abstract. Magnetic properties of FeSi1−xGex have been investigated using polycrystalline samples. A transition from nonmagnetic state with an energy gap for x = 0 to a weak ferromagnetic state for x = 0.5 has been confirmed, which was previously reported by Yeo et al. using single crystalline samples. Pauli-paramagnetic contribution to the low temperature susceptibility, χspin(0), has been estimated for the samples with x ≤ 0.3 by fitting the observed data. It significantly increases with the increase of x, reaching the value χspin(0) = 0.75×10 −3 emu/mol, which is comparable to those of the nearly ferromagnetic metals YCo2 and Pd. Using the Arrot plot, the parameter F1 of the spin-fluctuation theory has been estimated. F1 shows a drastic decrease from the order of 10 6 K for x = 0 to 9.5×10 3 K for x = 0.5, which is very similar to the x dependence of F1 in Y(Co1−xAlx)2 across the nonmagnetic-ferromagnetic phase boundary. These results suggest that the evolution of the magnetism in FeSi1−xGex can be well understood in terms of the transition from nearly ferromagnetic to weak itinerant ferromagnetic metal.

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Evolution of a metallic and magnetic state in (Fe,Mn)Si and Fe(Si,Ge)

Cited by 18 publications

References 8 publications

Pressure-induced insulator-metal transition of localized states inFeSi1−xGex

Pressure-induced insulator-metal transition of localized states inFeSi1−xGex

Electronic structure of Fe₄Si_4–xGe_x (x = 0–4) compounds: ab initio calculation

Magnetic study of FeSi_1−xGe_xacross the nonmagnetic-ferromagnetic transition

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Evolution of a metallic and magnetic state in (Fe,Mn)Si and Fe(Si,Ge)

Cited by 18 publications

References 8 publications

Pressure-induced insulator-metal transition of localized states inFeSi1−xGex

Pressure-induced insulator-metal transition of localized states inFeSi1−xGex

Electronic structure of Fe4Si4–xGex (x = 0–4) compounds: ab initio calculation

Magnetic study of FeSi1−xGexacross the nonmagnetic-ferromagnetic transition

Contact Info

Product

Resources

About

Electronic structure of Fe₄Si_4–xGe_x (x = 0–4) compounds: ab initio calculation

Magnetic study of FeSi_1−xGe_xacross the nonmagnetic-ferromagnetic transition