Point-contact spectroscopy of the relaxation dynamics of two-level systems upon structural changes in Ni-Nb glasses

O. P. Balkashin, I. K. Yanson, A. Halbritter, G. Mihály

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

The point-contact spectra (the energy dependence of the second derivatives of the current-voltage characteristics) of bimetal contacts of the amorphous alloy Ni59Nb41 with silver are investigated in the frequency range 103-5×109Hz. At low energies the spectral feature due to the scattering of conduction electrons on two-level tunneling systems in point contacts of the quenched alloy is clearly observed in the microwave region. This confirms the conclusion reached previously by the authors for homocontacts [O. P. Balkashin et al., Solid State Commun. 118, 623 (2001)] that rapidly relaxing two-level systems with a characteristic relaxation frequency Γ>1011Hz are present in metallic glasses. After a high-temperature annealing of the amorphous alloy (for 1 hour at T=800 °C) and its crystallization, the intensity of the spectral feature in the region of low voltages across the contact increases substantially. A sharp frequency dispersion of the amplitude of this feature is observed; it vanishes completely for measurements at frequencies below ∼5×109Hz. The data attest to the formation of qualitatively new, slowly relaxing two-level systems in the annealed Ni-Nb amorphous alloys. An estimate of the characteristic relaxation frequency of the two-level systems from the frequency dispersion of the measured signal gives a value Γ/2π≈0.7×109Hz. The possible causes of the formation of two-level systems in point contacts are discussed.

Original languageEnglish
Pages (from-to)123-129
Number of pages7
JournalLow Temperature Physics
Volume29
Issue number2
DOIs
Publication statusPublished - 2003

Fingerprint

glass
spectroscopy
bimetals
metallic glasses
conduction electrons
low voltage
frequency ranges
silver
crystallization
solid state
microwaves
annealing
energy
causes
electric potential
estimates
scattering

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

Cite this

Point-contact spectroscopy of the relaxation dynamics of two-level systems upon structural changes in Ni-Nb glasses. / Balkashin, O. P.; Yanson, I. K.; Halbritter, A.; Mihály, G.

In: Low Temperature Physics, Vol. 29, No. 2, 2003, p. 123-129.

Research output: Contribution to journalArticle

@article{7c920537780a467889f6b24e39deb96e,
title = "Point-contact spectroscopy of the relaxation dynamics of two-level systems upon structural changes in Ni-Nb glasses",
abstract = "The point-contact spectra (the energy dependence of the second derivatives of the current-voltage characteristics) of bimetal contacts of the amorphous alloy Ni59Nb41 with silver are investigated in the frequency range 103-5×109Hz. At low energies the spectral feature due to the scattering of conduction electrons on two-level tunneling systems in point contacts of the quenched alloy is clearly observed in the microwave region. This confirms the conclusion reached previously by the authors for homocontacts [O. P. Balkashin et al., Solid State Commun. 118, 623 (2001)] that rapidly relaxing two-level systems with a characteristic relaxation frequency Γ>1011Hz are present in metallic glasses. After a high-temperature annealing of the amorphous alloy (for 1 hour at T=800 °C) and its crystallization, the intensity of the spectral feature in the region of low voltages across the contact increases substantially. A sharp frequency dispersion of the amplitude of this feature is observed; it vanishes completely for measurements at frequencies below ∼5×109Hz. The data attest to the formation of qualitatively new, slowly relaxing two-level systems in the annealed Ni-Nb amorphous alloys. An estimate of the characteristic relaxation frequency of the two-level systems from the frequency dispersion of the measured signal gives a value Γ/2π≈0.7×109Hz. The possible causes of the formation of two-level systems in point contacts are discussed.",
author = "Balkashin, {O. P.} and Yanson, {I. K.} and A. Halbritter and G. Mih{\'a}ly",
year = "2003",
doi = "10.1063/1.1542411",
language = "English",
volume = "29",
pages = "123--129",
journal = "Soviet Journal of Low Temperature Physics (English Translation of Fizika Nizkikh Temperatur)",
issn = "1063-777X",
publisher = "American Institute of Physics Publising LLC",
number = "2",

}

TY - JOUR

T1 - Point-contact spectroscopy of the relaxation dynamics of two-level systems upon structural changes in Ni-Nb glasses

AU - Balkashin, O. P.

AU - Yanson, I. K.

AU - Halbritter, A.

AU - Mihály, G.

PY - 2003

Y1 - 2003

N2 - The point-contact spectra (the energy dependence of the second derivatives of the current-voltage characteristics) of bimetal contacts of the amorphous alloy Ni59Nb41 with silver are investigated in the frequency range 103-5×109Hz. At low energies the spectral feature due to the scattering of conduction electrons on two-level tunneling systems in point contacts of the quenched alloy is clearly observed in the microwave region. This confirms the conclusion reached previously by the authors for homocontacts [O. P. Balkashin et al., Solid State Commun. 118, 623 (2001)] that rapidly relaxing two-level systems with a characteristic relaxation frequency Γ>1011Hz are present in metallic glasses. After a high-temperature annealing of the amorphous alloy (for 1 hour at T=800 °C) and its crystallization, the intensity of the spectral feature in the region of low voltages across the contact increases substantially. A sharp frequency dispersion of the amplitude of this feature is observed; it vanishes completely for measurements at frequencies below ∼5×109Hz. The data attest to the formation of qualitatively new, slowly relaxing two-level systems in the annealed Ni-Nb amorphous alloys. An estimate of the characteristic relaxation frequency of the two-level systems from the frequency dispersion of the measured signal gives a value Γ/2π≈0.7×109Hz. The possible causes of the formation of two-level systems in point contacts are discussed.

AB - The point-contact spectra (the energy dependence of the second derivatives of the current-voltage characteristics) of bimetal contacts of the amorphous alloy Ni59Nb41 with silver are investigated in the frequency range 103-5×109Hz. At low energies the spectral feature due to the scattering of conduction electrons on two-level tunneling systems in point contacts of the quenched alloy is clearly observed in the microwave region. This confirms the conclusion reached previously by the authors for homocontacts [O. P. Balkashin et al., Solid State Commun. 118, 623 (2001)] that rapidly relaxing two-level systems with a characteristic relaxation frequency Γ>1011Hz are present in metallic glasses. After a high-temperature annealing of the amorphous alloy (for 1 hour at T=800 °C) and its crystallization, the intensity of the spectral feature in the region of low voltages across the contact increases substantially. A sharp frequency dispersion of the amplitude of this feature is observed; it vanishes completely for measurements at frequencies below ∼5×109Hz. The data attest to the formation of qualitatively new, slowly relaxing two-level systems in the annealed Ni-Nb amorphous alloys. An estimate of the characteristic relaxation frequency of the two-level systems from the frequency dispersion of the measured signal gives a value Γ/2π≈0.7×109Hz. The possible causes of the formation of two-level systems in point contacts are discussed.

UR - http://www.scopus.com/inward/record.url?scp=21144443600&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=21144443600&partnerID=8YFLogxK

U2 - 10.1063/1.1542411

DO - 10.1063/1.1542411

M3 - Article

VL - 29

SP - 123

EP - 129

JO - Soviet Journal of Low Temperature Physics (English Translation of Fizika Nizkikh Temperatur)

JF - Soviet Journal of Low Temperature Physics (English Translation of Fizika Nizkikh Temperatur)

SN - 1063-777X

IS - 2

ER -