Critical behavior in NaV2O5: the case of dielectric function and the aspect of universality

Temperature dependence in the interval 4.2-300 K and the critical behavior of the dielectric function along c-axis in NaV2O5 have been studied in the frequency range 1 MHz-1 GHz. These data were analyzed together with literature data concerning specific heat, magnetic losses and ultrasonic velocity. We found that all results support the idea about universality of the critical laws at the transition in NaV2O5 where different physical quantities demonstrate identical shape of the anomaly. Considerable deviations from the standard theory of the second order transition including asymmetry of the critical behavior above and below transition and appearance of the anomalous background are detected.