High frequency dielectric and magnetic anomaly at the phase transition in NaV2O5

Abstract

We found anomalies in the temperature dependence of the dielectric and the magnetic susceptibiliy of NaV_2O_5 in the microwave and far infrared frequency ranges. The anomalies occur at the phase transition temperature T_c, at which the spin gap opens. The real parts of the dielectric constants epsilon_a and epsilon_c decrease below T_c. The decrease of epsilon_a (except for the narrow region close to T_c) is proportional to the intensity of the x-ray reflection appearing at T_c. The dielectric constant anomaly can be explained by the zigzag charge ordering in the ab-plane appearing below T_c. The anomaly of the microwave magnetic losses is probably related to the coupling between the spin and charge degrees of freedom in vanadium ladders.

arXiv comment3 PS-figures, LATEX-text, new experimental data added, typos corrected

References in corpus (8)

• NaV_2O_5 as a quarter-filled ladder compound
• Study of the magnetic susceptibility in the spin-Peierls system CuGeO${}_3$
• A new view of the electronic structure of the spin-Peierls compound alpha'-NaV2O5
• Charged Magnons in NaV2O5
• Charge ordering and spin- Peierls transition in alpha'-NaV2O5
• Anomalous thermal conductivity of NaV2O5 as compared to conventional spin-Peierls system CuGeO3
• Interference of a first-order transition with the formation of a spin-Peierls state in alpha'-NaV2O5?
• Appearance of new lines and change in line shape in the IR spectrum of a NaV_2O_5 single crystal at the spin-Peierls transition

Cited by in corpus (6)

• Charge ordering and opening of spin gap in NaV_2O_5
• Charge Ordering and Spin Dynamics in NaV2O5
• Zigzag Charge Ordering in alpha'-NaV2O5
• High frequency ESR investigation on dynamical charge disproportionation and spin gap excitation in NaV_2O_5
• Unconventional anisotropic superexchange in NaV2O5
• Near degeneracy and pseudo Jahn-Teller effects in mixed-valence ladders: the phase transition in NaV${}_2$O${}_5$