Point-contact spectroscopy of relaxation dynamics of two-level systems at structure reconstruction of metal glasses Ni-Nb

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

Research output: Contribution to journalArticle

Abstract

The PC spectra (the energy dependences of the second derivatives of current-voltage characteristics) for bimetal contacts of an amorphous alloy of Ni59Nb41 with silver are studied in a frequency band 103 -5·109 Hz. In the contacts from the quenched alloy the spectral feature at small energies caused by conduction electrons scattering in the two-level tunnel systems (TLS) is clearly seen in a microwave range. This confirms our previous conclusion for homocontacts (O.P.Balkashin et al., Solid State Commun. 118, 623 (2001)) about the availability of fast relaxing TLS with characteristic relaxation frequency Γ > 1011 Hz in metal glasses. After a high temperature annealing of the amorphous alloy (T = 800°C for 1 hours) and its crystallization the spectral feature intensity in the region of small biases on the contact increased essentially. A sharp frequency dispersion of the feature amplitude to its complete disappearance is detected in the measurements at frequencies up to ∼ 5·109 Hz. The data obtained testify to the formation of qualitatively new slowly relaxing TLS in the annealed amorphous alloys Ni-Nb. The estimation of the characteristic relaxation frequency from the frequency dispersion of the signal measured gives Γ/2π ≈ 0.7·109 Hz. Possible reasons for formation of two-level systems in point contacts are considered.

Original languageEnglish
Pages (from-to)169-178
Number of pages10
JournalLow Temperature Physics
Volume29
Issue number2
Publication statusPublished - Feb 2003

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glass
metals
spectroscopy
tunnels
bimetals
conduction electrons
availability
electron scattering
silver
crystallization
solid state
microwaves
annealing
energy
electric potential

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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Point-contact spectroscopy of relaxation dynamics of two-level systems at structure reconstruction of metal glasses Ni-Nb. / Balkashin, O. P.; Yanson, I. K.; Halbritter, A.; Mihály, G.

In: Low Temperature Physics, Vol. 29, No. 2, 02.2003, p. 169-178.

Research output: Contribution to journalArticle

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