Microwave EPR spectroscopy of cobalt-doped germanium cuprate

S. V. Demishev, A. V. Semeno, N. E. Sluchanko, N. A. Samarin, A. A. Pronin, Y. Inagaki, S. Okubo, H. Ohta, Y. Oshima, L. I. Leonyuk

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

Resonance magnetoabsorption spectra of CuGeO3 single crystals containing 2% Co impurity have been studied in the frequency range 60-360 GHz in magnetic fields of up to 16 T and in the temperature interval 2-60 K with the magnetic field B aligned parallel to the a crystallographic axis. In addition to the Cu2+ chain resonance, a new absorption line (unobserved previously in doped CuGeO3 and deriving apparently from the Co 2+ ions) was detected in EPR spectra. Quantitative analysis of the spectra suggests that the spin-Peierls transition occurs in about 10% Cu 2+ chains, while the spin-Peierls state in the remaining 90% chains is completely destroyed by cobalt doping. The results obtained reveal considerable deviations from the universally accepted scenario of CuGeO 3 doping and are discussed within alternative theoretical models, namely, the quantum critical behavior (based on the EPR theory for quasi-one-dimensional systems) and a three-dimensional antiferromagnet with the Néel temperature lowered by disorder.

Original languageEnglish
Pages (from-to)2238-2248
Number of pages11
JournalPhysics of the Solid State
Volume46
Issue number12
DOIs
Publication statusPublished - 2004
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Fingerprint

Dive into the research topics of 'Microwave EPR spectroscopy of cobalt-doped germanium cuprate'. Together they form a unique fingerprint.

Cite this