Fig. 3: Low-temperature dielectric measurements.
The magnetic field-dependent complex permittivity Δε* in the vicinity of Hc for different frequencies and temperatures. In a the evolution of \({{\Delta }}\varepsilon ^{\prime}\) from a dispersive feature at a higher temperature into a peak with no dispersion up to approximately 1 GHz (green) with a steep drop above this frequency with cooling is shown. The dielectric loss Δε″ in b also changes from a broad, dispersive maximum at higher temperatures observed for all frequencies to a, in the frequency domain, a narrow peak located roughly between 2 and 3 GHz at low temperature.
