The Effect of Spin-Peierls Instability Suppression in Nanometer-Scale-Sized CuGeO3 Crystals

• Published in: Applied magnetic resonance Vol. 47; no. 8; pp. 881 - 893
• Main Authors: Semeno, A. V., Gilmanov, M. I., Kuznetzov, A. V., Melnik, N. N., Grigorjeva, A. V., Barulin, A. V., Gudilin, E. A., Demishev, S. V.
• Format: Journal Article
• Language: English
• Published: Vienna Springer Vienna 01.08.2016; Springer Nature B.V
• Subjects: Asymmetry; Atoms and Molecules in Strong Fields; Comparative studies; Crystal structure; Crystallites; Dimerization; Electron paramagnetic resonance; Electron spin; Electrons; High temperature; Laser Matter Interaction; Magnetic permeability; Magnetic properties; Magnets; Morphology; Nanocrystals; Nanowires; Organic Chemistry; Physical Chemistry; Physics; Physics and Astronomy; Size effects; Solid State Physics; Spectroscopy/Spectrometry; Spectrum analysis; Spin resonance; Synthesis; Temperature dependence; Germanium Dioxide; Weiss Temperature; Electron Spin Resonance; Surface Disorder; Electron Spin Resonance Line
• ISSN: 0937-9347; 1613-7507
• DOI: 10.1007/s00723-016-0788-2

In this work, we study the influence of size effects on magnetic properties of quasi-one-dimensional spin-Peierls magnet CuGeO 3 . It was found that the reduction of the crystallite’s size to nanometer scale (~300 × 30 nm) leads to full suppression of spin-Peierls transition, which takes place in the bulk material at T ≈ 14  K. Combined analysis of electron spin resonance (ESR) and magnetic susceptibility measurements allowed separating of the dynamic magnetization of Cu chains χ E S R . Its temperature dependence is found to be typical for one-dimensional magnets with quantum critical (QC) behavior and is described by Curie–Weiss law χ ∼ 1 T + Θ at high temperatures, turning into power law asymptotic χ ∼ T - α ( α < 1 ) with temperature decrease. The data for two samples with different synthesis times (24 and 96 h) are analyzed in the framework of the QC behavior model. Although the values of magnetic parameters strongly depend on the synthesis time, the qualitative behavior is similar for both samples, which is shown by a comparative study of QC behavior of CuGeO 3 doped with 1 % of Fe. We argue that the reason for the observed behavior is the competition between the onset of the staggered magnetic field and dimerization effects.