<abstract xml:lang="en" xmlns="http://www.w3.org/1999/xhtml"><p>The temperature dependence of dc magnetization and electron paramagnetic resonance (EPR) spectra of the β-Cu3Fe4V6O24 multicomponent vanadate were investigated. Dc magnetic measurements showed the presence of strong antiferromagnetic interactions (Curie-Weiss temperature, Θ ∼ 80 K) at high temperatures, while zero-field-cooled (ZFC) magnetization revealed a cusp-like maximum in low fields at Tf1 = 4.4 K, which coincides with the splitting of the ZFC and FC curves. Another maximum was registered at Tf2 = 3.0 K. These two temperatures (Tf1 and Tf2) could be regarded as freezing temperatures in the spin glass state of two magnetic sublattices of Fe1 and Fe2 ions. The EPR spectrum of β-Cu3Fe4V6O24 is dominated by a nearly symmetrical, very intense and broad resonance line centered at g
                        eff ∼ 2.0 that could be attributed to iron ions. Below 10 K, an additional EPR spectrum with g
                        1 = 2.018(1) and g
                        2 = 2.175(1) appears, as well as a very weak line at geff = 1.99(1). The former spectrum is probably is due to divalent copper ions, and the latter line due to vanadium V4+ complexes. The temperature dependence of EPR parameters (g-factor, linewidth, integrated intensity) was determined in the range of 3–300 K. Two low-temperature maxima in the temperature dependence of the integrated intensity (at 40 and 6 K) were fitted with a function suitable for pairs of exchange-coupled Fe3+ ions. A comparison of dc magnetic susceptibility and EPR integrated intensity indicates the presence of spin clusters, which play an important role in determining the low-temperature magnetic response of β-Cu3Fe4V6O24.</p></abstract>

The temperature dependence of dc magnetization and electron paramagnetic resonance (EPR) spectra of the β-Cu3Fe4V6O24 multicomponent vanadate were investigated. Dc magnetic measurements showed the presence of strong antiferromagnetic interactions (Curie-Weiss temperature, Θ ∼ 80 K) at high temperatures, while zero-field-cooled (ZFC) magnetization revealed a cusp-like maximum in low fields at Tf1 = 4.4 K, which coincides with the splitting of the ZFC and FC curves. Another maximum was registered at Tf2 = 3.0 K. These two temperatures (Tf1 and Tf2) could be regarded as freezing temperatures in the spin glass state of two magnetic sublattices of Fe1 and Fe2 ions. The EPR spectrum of β-Cu3Fe4V6O24 is dominated by a nearly symmetrical, very intense and broad resonance line centered at g
                        eff ∼ 2.0 that could be attributed to iron ions. Below 10 K, an additional EPR spectrum with g
                        1 = 2.018(1) and g
                        2 = 2.175(1) appears, as well as a very weak line at geff = 1.99(1). The former spectrum is probably is due to divalent copper ions, and the latter line due to vanadium V4+ complexes. The temperature dependence of EPR parameters (g-factor, linewidth, integrated intensity) was determined in the range of 3–300 K. Two low-temperature maxima in the temperature dependence of the integrated intensity (at 40 and 6 K) were fitted with a function suitable for pairs of exchange-coupled Fe3+ ions. A comparison of dc magnetic susceptibility and EPR integrated intensity indicates the presence of spin clusters, which play an important role in determining the low-temperature magnetic response of β-Cu3Fe4V6O24.

Study of magnetic inhomogeneity in β-Cu3Fe4V6O24
                  

Solid State Physics, Department of Physics, University of Athens, Panepistimiopolis, 15 784, Zografos, Athens, Greece

Institute of Physics, West Pomeranian University of Technology, Al. Piastow 48, 70-311, Szczecin, Poland

Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 36/42, 02-688, Warsaw, Poland

Department of Inorganic and Analytical Chemistry, West Pomeranian University of Technology, Al. Piastow 42, 70-065, Szczecin, Poland

Materials Science-Poland

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

{"article-title":"Study of magnetic inhomogeneity in β-Cu3Fe4V6O24"}

The temperature dependence of dc magnetization and electron paramagnetic resonance (EPR) spectra of the β-Cu3Fe4V6O24 multicomponent vanadate were...

Study of magnetic inhomogeneity in β-Cu3Fe4V6O24

Pubblicato online: 16 giu 2012

Pagine: 1 - 9

DOI: https://doi.org/10.2478/s13536-012-0002-7

Parole chiave
EPR vanadates

© 2012 Wroclaw University of Technology

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Study of magnetic inhomogeneity in β-Cu3Fe4V6O24

Pubblicato online: 16 giu 2012

Pagine: 1 - 9

DOI: https://doi.org/10.2478/s13536-012-0002-7

Parole chiaveEPR vanadates

© 2012 Wroclaw University of Technology

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Parole chiave
EPR vanadates