Negative Magnetoresistivity in Dilute Alloys

Béal-Monod, M. T.; Weiner, R. A.

doi:10.1103/physrev.170.552

Cited by 246 publications

(61 citation statements)

References 24 publications

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“…The origin of the rise in resistivity below 50 K is not clear; however, the fielddependent magnetoresistance ͑MR͒, defined as ⌬ / 0 ϭ͓ (H)Ϫ (0)͔/ (0), shown in Fig. 7͑a͒ obeys the simple scaling relationship described by Beal-Monod and Weiner 13 for a Kondo system with TӷT K : ⌬ ϰ f (M ), where M is the magnetization. By plotting the magnetoresistance vs M ϷH/(Tϩ ) ͓Fig.…”

Section: Resultsmentioning

confidence: 99%

Structure and physical properties of the quaternary Remeika-phase compoundYb5Pt6In
Moshopoulou
¹
,
Hundley
²
,
Movshovich
³

et al. 1999
Phys. Rev. B
5
1
0
0
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Section: Resultsmentioning

confidence: 99%

Structure and physical properties of the quaternary Remeika-phase compoundYb5Pt6In
Moshopoulou
¹
,
Hundley
²
,
Movshovich
³

et al. 1999
Phys. Rev. B
5
1
0
0
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“…The pure negative MR has been extracted after correcting the total MR by the normal MR which has been extrapolated for T < T min using the Kohler rule. For the Kondo effect, the MR is predicted to vary approximately as < S > 2 , the square of thermal average of localized moment, for temperatures T > T K [11,12] what is the relevant case here. The field dependence of the negative MR should be very close to the square of the Brillouin function, as we observe in Fig.7.…”

Section: Low Temperature Magnetotransport Propertiesmentioning

confidence: 99%

Dominant role of impurity scattering over crystalline anisotropy for magnetotransport properties in the quasi-one-dimensional hollanditeBa1.2Rh8O16
Pautrat
¹
,
Kobayashi
²

2010
Phys. Rev. B
12
2
9
1
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Angular magnetotransport measurements have been performed to tackle the origin of the magnetoresistance in the quasi-1D Hollandite Ba1.2Rh8O16. Three samples of different impurities amount were measured. We observe that the low temperature resistivity upturn is not due to a charge density wave transition, and a dominant role of impurities scattering for low temperature transport properties is instead demonstrated. The components of magnetoresistance were separated by using the Kohler plot and the angular dependency of the resistance under magnetic field. It shows the major contribution of an isotropic, likely spin driven, negative magnetoresistance. Galvanomagnetic characteristics are then consistent with a Kondo effect and appear to be essentially 3D at low temperature.

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“…These observations have been made possible by the presence of free spins in granular Aluminum films, which we confirm here by direct µSR measurements. Interaction of these spins with conduction electrons results in a negative magneto-resistance [5]. We have used it as a tool to follow changes of the effective Fermi energy of the granular medium as the transition is being approached.…”

mentioning

confidence: 99%

“…In the presence of a magnetic field oriented along the positive z direction, which tends to orient the magnetic moment of the impurities along this direction, there are more scattering events of a spin down electron into a spin up than that of a spin up electron scattering into a spin down. But the lower density of available states below the Fermi level where spin up electrons end up due to the Zeeman energy gain forbids these scattering processes because of the exclusion principle [5]. The total contribution of the spin-flip scattering amplitudes to the resistivity is decreased.…”

mentioning

confidence: 99%

Mott transition in granular aluminum

et al. 2015

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The presence of free spins in granular Al films is directly demonstrated by µSR measurements. A Mott transition is observed by probing the increase of the spin-flip scattering rate of conduction electrons as the nano-size metallic grains are being progressively decoupled. Analysis of the magnetoresistance in terms of an effective Fermi energy shows that it becomes of the order of the grains electrostatic charging energy at a room temperature resistivity ρ ≈ 50, 000 µΩ cm, at which a metal to insulator transition is known to exist. As this transition is approached the magneto-resistance exhibits a Heavy-Fermion like behavior, consistent with an increased electron effective mass.PACS numbers: 74.81. Bd, 71.30.+h, 72.15.Qm, 74.25.Ha Thanks to advances in the development of the Density functional Mean Field Theory (DMFT) [1], considerable advances have been made in recent years towards a detailed understanding of the Mott metal to insulator transition, predicted to occur when the electron-electron interaction is of the order of the bandwidth [2]. However the experimental observation of this transition has remained a challenge in three dimensional systems. This is because in a homogeneous metal the Coulomb interaction is by several orders of magnitude smaller than the bandwidth, even in the presence of a relatively high concentration of impurities [3,4].We show here that a Mott transition takes place in granular metals, as nano-size grains are being decoupled from each other by a progressive reduction of the intergrain tunneling probability. Two of the main features of this transition predicted by DMFT theory, an increase of the electron effective mass and a non-critical behavior of the electronic density of states as the transition is approached, have been observed. These observations have been made possible by the presence of free spins in granular Aluminum films, which we confirm here by direct µSR measurements. Interaction of these spins with conduction electrons results in a negative magneto-resistance [5]. We have used it as a tool to follow changes of the effective Fermi energy of the granular medium as the transition is being approached. When it occurs, at a room temperature resistivity of about 50,000 µΩcm, we find that the effective Fermi energy is of the order of the grain's charging electrostatic energy. The superconducting critical temperature of the films remains relatively high up to close to the transition, indicating there is no drastic reduction of the density of states up to the transition.Low energy muon spin rotation/relaxation (LE µSR) experiments [6] were performed on film not too close to the MIT transition. The measurements were performed at the Swiss Muon Source on the µE4 beam-line, at the Paul Scherrer Institute, in Switzerland. With implantation energy of 10 keV all the muons stop in the 100 nm FIG. 1. Temperature dependence of the muon spin relaxation rate of electronic origin λ for a sample with ρ300K ≈ 140 µΩcm. λ appears to saturate around a temperature where ρ(T ) starts to increa...

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Negative Magnetoresistivity in Dilute Alloys

Cited by 246 publications

References 24 publications

Structure and physical properties of the quaternary Remeika-phase compoundYb5Pt6In
Moshopoulou
¹
,
Hundley
²
,
Movshovich
³

et al. 1999
Phys. Rev. B
5
1
0
0
View full text Add to dashboard Cite

Structure and physical properties of the quaternary Remeika-phase compoundYb5Pt6In
Moshopoulou
¹
,
Hundley
²
,
Movshovich
³

et al. 1999
Phys. Rev. B
5
1
0
0
View full text Add to dashboard Cite

Dominant role of impurity scattering over crystalline anisotropy for magnetotransport properties in the quasi-one-dimensional hollanditeBa1.2Rh8O16
Pautrat
¹
,
Kobayashi
²

2010
Phys. Rev. B
12
2
9
1
View full text Add to dashboard Cite

Mott transition in granular aluminum

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Negative Magnetoresistivity in Dilute Alloys

Cited by 246 publications

References 24 publications

Structure and physical properties of the quaternary Remeika-phase compoundYb5Pt6InMoshopoulou1, Hundley2, Movshovich3 et al. 1999Phys. Rev. B5100View full textAdd to dashboardCite

Structure and physical properties of the quaternary Remeika-phase compoundYb5Pt6InMoshopoulou1, Hundley2, Movshovich3 et al. 1999Phys. Rev. B5100View full textAdd to dashboardCite

Dominant role of impurity scattering over crystalline anisotropy for magnetotransport properties in the quasi-one-dimensional hollanditeBa1.2Rh8O16Pautrat1, Kobayashi2 2010Phys. Rev. B12291View full textAdd to dashboardCite

Mott transition in granular aluminum

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Structure and physical properties of the quaternary Remeika-phase compoundYb5Pt6In
Moshopoulou
¹
,
Hundley
²
,
Movshovich
³

et al. 1999
Phys. Rev. B
5
1
0
0
View full text Add to dashboard Cite

Structure and physical properties of the quaternary Remeika-phase compoundYb5Pt6In
Moshopoulou
¹
,
Hundley
²
,
Movshovich
³

et al. 1999
Phys. Rev. B
5
1
0
0
View full text Add to dashboard Cite

Dominant role of impurity scattering over crystalline anisotropy for magnetotransport properties in the quasi-one-dimensional hollanditeBa1.2Rh8O16
Pautrat
¹
,
Kobayashi
²

2010
Phys. Rev. B
12
2
9
1
View full text Add to dashboard Cite