Finite-size effects in the low-temperature resistivity of CuCr films

DiTusa, J. F.; Lin, Kai; Park, M.; Isaacson, M.; Parpia, J. M.

doi:10.1103/physrevlett.68.678

Cited by 52 publications

(31 citation statements)

References 11 publications

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“…22,23,25 However, a number of experimental observations were made on the size dependence of the Kondo effect, mostly using thin films or thin wires of very dilute Kondo alloys, e.g., AuFe 22,23,26 -28 or CuCr. 29,30 No clear picture emerges from these experimental results, since in some cases a size effect is indeed observed 22,26 -28,30 and in other cases not. 23,29 What these results have in common though, is that the Kondo temperature appears to be constant.…”

Section: A Size Dependence Of Single-impurity Kondo Scatteringmentioning

confidence: 55%

Thickness dependence of the ground-state properties of thin films of the heavy-fermion compoundCeCu6

et al. 2001

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High-quality thin polycrystalline films of the heavy-fermion compound CeCu 6 were prepared by sputter deposition. The thicker of these films ͑with thickness up to around 200 nm͒ reproduce the properties of the bulk compound CeCu 6 . As the thickness of the films is decreased, our measurements display strong deviations from the bulk properties, namely, a suppression of the heavy-fermion state. We show that possible ''external'' effects, such as disorder, oxidation and morphology can be excluded and that this size effect is therefore an intrinsic property of CeCu 6 . In addition, we investigate possible scenarios explaining the size effect, and find that the proximity of CeCu 6 to a quantum phase transition can account for this striking result.

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Section: A Size Dependence Of Single-impurity Kondo Scatteringmentioning

confidence: 55%

Thickness dependence of the ground-state properties of thin films of the heavy-fermion compoundCeCu6

et al. 2001

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“…1, the surface-induced magnetic anisotropy for impurity spins is very sensitive to the shape and size of grains. This implies that the apparent discrepancy between various experimental results [1][2][3][4] for the size dependence of the Kondo resistivity can be linked to different microstructures of the samples.…”

Section: Surface-induced Magnetic Anisotropy In Grainsmentioning

confidence: 94%

Surface-induced magnetic anisotropy for impurity spins in granular AuFe films

Gladilin

Фомин

Devreese

2001

Physica B: Condensed Matter

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The theory of the surface-induced anisotropy is extended to the case of granular films of dilute magnetic alloys. Since the surface-induced blocking of a magnetic-impurity spin appears to be very sensitive to the specific polycrystalline structure, we speculate that the apparent discrepancy between the experimental results of different groups for the size dependence of the Kondo resistivity can be linked to different microstructure of the samples. We apply our model to calculate the magnetization of impurity spins in small AuFe grains and to interpret the experimental data on the anomalous Hall effect in thin Fe doped Au films.

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“…%) the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction between the randomly distributed impurity spins competes with the Kondo effect and causes a freezing of the impurity spins into a disordered configuration called a spin glass. This is reflected by the appearance of a typical broad maximum in r͑T ͒ since the spin scattering rate again decreases at the lowest temperatures due to the freezing process.Recent experimental work has addressed the existence of intrinsic length scales for both the Kondo effect and the spin glass freezing process [2][3][4][5][6]. The results have so far been controversial: While some groups [2,3] report a pronounced depression of the Kondo slope with decreasing film thickness and wire width, other authors claim that the observed size effects are small and can moreover be explained quantitatively in terms of disorder enhanced electron-electron interaction effects [5,6].…”

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confidence: 99%

Size Dependent Thermopower in Mesoscopic AuFe Wires

et al. 1998

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We have combined electron heating experiments and noise thermometry to perform quantitative measurements of the thermopower in mesoscopic samples. This new measuring technique allows us to detect finite size effects in the thermopower of narrow AuFe wires with an Fe concentration ranging from 50 to 3000 ppm. The size effects emerge when reducing the width of the wires below Ӎ300 nm and may be related to a spin-orbit induced magnetic anisotropy close to the wire surface.[ S0031-9007(98) The scattering of conduction electrons at transition metal impurity spins (e.g., Fe, Cr, and Mn) substantially alters the low temperature properties of noble metals (e.g., Au, Ag, and Cu) [1]. For small concentrations (ϳ100 ppm) of the magnetic dopant the Kondo effect gives rise to a logarithmic increase of the resistivity r͑T ͒. Below the Kondo temperature T K a compensation cloud of conduction electrons is formed around the impurity spins which gradually cancels their magnetic moment. At higher concentrations (ϳ1 at. %) the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction between the randomly distributed impurity spins competes with the Kondo effect and causes a freezing of the impurity spins into a disordered configuration called a spin glass. This is reflected by the appearance of a typical broad maximum in r͑T ͒ since the spin scattering rate again decreases at the lowest temperatures due to the freezing process.Recent experimental work has addressed the existence of intrinsic length scales for both the Kondo effect and the spin glass freezing process [2][3][4][5][6]. The results have so far been controversial: While some groups [2,3] report a pronounced depression of the Kondo slope with decreasing film thickness and wire width, other authors claim that the observed size effects are small and can moreover be explained quantitatively in terms of disorder enhanced electron-electron interaction effects [5,6]. It was also noted that structural disorder may have an important influence on the spin dependent part of r͑T ͒ for Kondo alloys [7] as well as for more concentrated spin glass alloys where a damping of the RKKY interaction occurs [6,8].Theoretical calculations have shown that in the single impurity limit spin-orbit interactions can induce a size dependent magnetic anisotropy which results in a size dependent resistivity [9]. For more disordered samples, an interplay between weak localization and the Kondo effect has been predicted which can account for both a disorder effect and a size effect [10]. In order to address the open questions related to the size effects,

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Finite-size effects in the low-temperature resistivity of CuCr films

Cited by 52 publications

References 11 publications

Thickness dependence of the ground-state properties of thin films of the heavy-fermion compoundCeCu6

Thickness dependence of the ground-state properties of thin films of the heavy-fermion compoundCeCu6

Surface-induced magnetic anisotropy for impurity spins in granular AuFe films

Size Dependent Thermopower in Mesoscopic AuFe Wires

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