Use of finite size and applied magnetic field to characterize the interimpurity interaction in a spin glass

Kr, Lane; Park, M; Ms, Isaacson; Jm, Parpia

doi:10.1103/physrevb.51.945

Cited by 12 publications

(10 citation statements)

References 15 publications

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“…This field is much smaller than the estimate of ⌬ c /g B ϳ 20 T obtained above from the position of V max in zero field. In contrast to the results of Lane et al 3 we find little or no size dependence of B 0 .…”

Section: Finite Magnetic Field Resultscontrasting

confidence: 99%

“…This field is, however, at least 20 T for our samples and could not be tested in our experiment. Therefore, the question of whether the spin-spin interaction between paramagnetic impurities is ''size dependent,'' either decreasing 3,7,9 or increasing, 15 remains open.…”

Section: Discussionmentioning

confidence: 99%

“…A size effect study by Lane et al 3 on CuCr concluded that there is a clear reduction of Kondo slope upon decreasing of the film thickness from about 170 nm to 15 nm, and a parameter H 0 identified with the internal (s-s) field was also observed to decrease. Hoines and co-workers 9 found a diminished freezing temperature for thin (р1 nm͒ CuMn and AgMn samples, and DiTusa et al 7 reported T f to drop and T K to remain the same when measuring on 1 m and thinner CuCr samples.…”

Section: Previous Work On Size Dependencesmentioning

confidence: 99%

“…The resistivity versus temperature (T) has been measured in mesoscopic samples by different authors in a variety of magnetic alloys. [3][4][5][6][7][8][9][10] Size dependences in Kondo scattering and spin freezing have been observed in some experiments, but the results contradict each other, e.g., Refs. 4 and 6.…”

Section: Introductionmentioning

confidence: 99%

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Size-dependence study of the spin glassCuMn (1%)

et al. 1996

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We present a point-contact spectroscopy study on the spin glass CuMn ͑1%͒ using a mechanically controllable break junction. Here we can continuously vary the contact size d from 1 m down to the atomic regime and thereby investigate size effects in spin-spin ͑spin glass͒ and spin-conduction electron ͑Kondo͒ interactions. Differential resistance dV/dI as a function of bias voltage V has been determined for the above alloy at various d and in different applied magnetic fields up to 10 T. A characteristic spin glass behavior is found for dV/dI vs V at large d which mimics the bulk resistivity (T). A magnetic field enhances the spin glass minimum at zero bias at the cost of the Kondo peak at higher bias. As d is reduced the dV/dI behavior becomes more Kondo-like; i.e., a more pronounced negative slope emerges. Finally for d values of a few angstroms a pure Kondo response is found. Our results can be interpreted with a model whereby T K strongly increases as d decreases, thus suppressing the spin glass features.

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Section: Finite Magnetic Field Resultscontrasting

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Previous Work On Size Dependencesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Size-dependence study of the spin glassCuMn (1%)

et al. 1996

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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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