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Anisotropic giant magnetoresistance in NbSb2.

Wang K, Graf D, Li L, Wang L, Petrovic C - Sci Rep (2014)

Bottom Line: The magnetic field response of the transport properties of novel materials and then the large magnetoresistance effects are of broad importance in both science and application.Magnetoresistance is significantly suppressed but the metal-semiconductor-like transition persists when the current is along the ac-plane.The large MR is attributed to the change of the Fermi surface induced by the magnetic field which is related to the Dirac-like point, in addition to orbital MR expected for high mobility metals.

View Article: PubMed Central - PubMed

Affiliation: Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973 USA.

ABSTRACT
The magnetic field response of the transport properties of novel materials and then the large magnetoresistance effects are of broad importance in both science and application. We report large transverse magnetoreistance (the magnetoresistant ratio ~ 1.3 × 10(5)% in 2 K and 9 T field, and 4.3 × 10(6)% in 0.4 K and 32 T field, without saturation) and field-induced metal-semiconductor-like transition, in NbSb2 single crystal. Magnetoresistance is significantly suppressed but the metal-semiconductor-like transition persists when the current is along the ac-plane. The sign reversal of the Hall resistivity and Seebeck coefficient in the field, plus the electronic structure reveal the coexistence of a small number of holes with very high mobility and a large number of electrons with low mobility. The large MR is attributed to the change of the Fermi surface induced by the magnetic field which is related to the Dirac-like point, in addition to orbital MR expected for high mobility metals.

No MeSH data available.


The anisotropic giant magnetoresistance of NbSb2.(a) A Kohler plot using  for NbSb2 with the current parallel to the b-axis and the magnetic field perpendicular to the current. Inset shows low field part enlarged for clarity. (b) The ρ(T) with the current parallel to b-axis and the magnetic field parallel to the current (parallel to the b-axis. (c) The ρ(T) with the current parallel to ac-plane and the magnetic field perpendicular to the current (parallel to the b-axis.
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f2: The anisotropic giant magnetoresistance of NbSb2.(a) A Kohler plot using for NbSb2 with the current parallel to the b-axis and the magnetic field perpendicular to the current. Inset shows low field part enlarged for clarity. (b) The ρ(T) with the current parallel to b-axis and the magnetic field parallel to the current (parallel to the b-axis. (c) The ρ(T) with the current parallel to ac-plane and the magnetic field perpendicular to the current (parallel to the b-axis.

Mentions: The external magnetic field significantly enhances the low-temperature resistivity and also changes its temperature-dependence. The ρ(T) is metallic in 1 T [Fig. 1(c)] but the slope increases with temperature decrease from 300 K. At about 300 K the ρ(T) shows a minimum and then increases with further decrease in temperature, which is similar to the metal-semiconductor crossover induced by external field observed in PtSn4, PdCoO2 and WTe22223. The resistivity nearly saturates below 10 K and its value increases from 0.009 mΩ cm in zero field to 0.02 mΩ cm in 1 T field. Higher field induces higher metal-semiconductor crossover temperature and larger MR. In 9 T field, the MR ratio approaches ~1.3 × 105% in 2 K (as shown in Fig. 1(d)) and the metal-semiconductor crossover temperature is about 70 K. The magnetic field dependence of the MR (as shown in Fig. 1(d)) can be described very well by the parabolic behavior (the red line is the fitting result using MR = aB2). With increasing temperature, MR is suppressed significantly but the ratio is still around 80% at 300 K [Fig. 1(d) inset]. Magnetotransport in semiclassical single-band metals scales as MR = f(Hτ) = F(H/ρ0) with the assumption of the single scattering time τ, i.e. 1/τ(T) ∝ ρ0(T)24. MR of NbSb2 in high field shows but deviates somewhat from Kohler scaling at low temperatures (Fig. 2(a)). The low field MR (inset of Fig. 2(a)) does not follow H1.8 dependence but overall satisfies the scaling. The MR and metal-semiconductor-like transition is observed in several crystals from different batches, showing very good repeatability (See Supplementary Figure 2).


Anisotropic giant magnetoresistance in NbSb2.

Wang K, Graf D, Li L, Wang L, Petrovic C - Sci Rep (2014)

The anisotropic giant magnetoresistance of NbSb2.(a) A Kohler plot using  for NbSb2 with the current parallel to the b-axis and the magnetic field perpendicular to the current. Inset shows low field part enlarged for clarity. (b) The ρ(T) with the current parallel to b-axis and the magnetic field parallel to the current (parallel to the b-axis. (c) The ρ(T) with the current parallel to ac-plane and the magnetic field perpendicular to the current (parallel to the b-axis.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4256591&req=5

f2: The anisotropic giant magnetoresistance of NbSb2.(a) A Kohler plot using for NbSb2 with the current parallel to the b-axis and the magnetic field perpendicular to the current. Inset shows low field part enlarged for clarity. (b) The ρ(T) with the current parallel to b-axis and the magnetic field parallel to the current (parallel to the b-axis. (c) The ρ(T) with the current parallel to ac-plane and the magnetic field perpendicular to the current (parallel to the b-axis.
Mentions: The external magnetic field significantly enhances the low-temperature resistivity and also changes its temperature-dependence. The ρ(T) is metallic in 1 T [Fig. 1(c)] but the slope increases with temperature decrease from 300 K. At about 300 K the ρ(T) shows a minimum and then increases with further decrease in temperature, which is similar to the metal-semiconductor crossover induced by external field observed in PtSn4, PdCoO2 and WTe22223. The resistivity nearly saturates below 10 K and its value increases from 0.009 mΩ cm in zero field to 0.02 mΩ cm in 1 T field. Higher field induces higher metal-semiconductor crossover temperature and larger MR. In 9 T field, the MR ratio approaches ~1.3 × 105% in 2 K (as shown in Fig. 1(d)) and the metal-semiconductor crossover temperature is about 70 K. The magnetic field dependence of the MR (as shown in Fig. 1(d)) can be described very well by the parabolic behavior (the red line is the fitting result using MR = aB2). With increasing temperature, MR is suppressed significantly but the ratio is still around 80% at 300 K [Fig. 1(d) inset]. Magnetotransport in semiclassical single-band metals scales as MR = f(Hτ) = F(H/ρ0) with the assumption of the single scattering time τ, i.e. 1/τ(T) ∝ ρ0(T)24. MR of NbSb2 in high field shows but deviates somewhat from Kohler scaling at low temperatures (Fig. 2(a)). The low field MR (inset of Fig. 2(a)) does not follow H1.8 dependence but overall satisfies the scaling. The MR and metal-semiconductor-like transition is observed in several crystals from different batches, showing very good repeatability (See Supplementary Figure 2).

Bottom Line: The magnetic field response of the transport properties of novel materials and then the large magnetoresistance effects are of broad importance in both science and application.Magnetoresistance is significantly suppressed but the metal-semiconductor-like transition persists when the current is along the ac-plane.The large MR is attributed to the change of the Fermi surface induced by the magnetic field which is related to the Dirac-like point, in addition to orbital MR expected for high mobility metals.

View Article: PubMed Central - PubMed

Affiliation: Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973 USA.

ABSTRACT
The magnetic field response of the transport properties of novel materials and then the large magnetoresistance effects are of broad importance in both science and application. We report large transverse magnetoreistance (the magnetoresistant ratio ~ 1.3 × 10(5)% in 2 K and 9 T field, and 4.3 × 10(6)% in 0.4 K and 32 T field, without saturation) and field-induced metal-semiconductor-like transition, in NbSb2 single crystal. Magnetoresistance is significantly suppressed but the metal-semiconductor-like transition persists when the current is along the ac-plane. The sign reversal of the Hall resistivity and Seebeck coefficient in the field, plus the electronic structure reveal the coexistence of a small number of holes with very high mobility and a large number of electrons with low mobility. The large MR is attributed to the change of the Fermi surface induced by the magnetic field which is related to the Dirac-like point, in addition to orbital MR expected for high mobility metals.

No MeSH data available.