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The complex dielectric response of Bi 1.5 Zn 1.0 Nb 1.5 O 7 cubic pyrochlore ceramics was investigated between 100 Hz and 100 THz by a combination of low-frequency capacitance bridges, a high-frequency coaxial technique, time domain transmission THz spectroscopy, and infrared spectroscopy. The data obtained between 10 K and 400 K revealed glasslike dielectric behavior: dielectric relaxation is observed over a wide frequency and temperature range, and the dielectric permittivity and loss maxima shift to higher temperature values by almost 200 K with increasing measuring frequency. The distribution of relaxation frequencies broadens on cooling and can be described by a uniform distribution. The high-frequency end of the distribution at∼ 10 11 Hz is almost temperature independent and its low-frequency end obeys the Arrhenius Law with an activation energy of∼ 0.2 eV. The relaxation is assigned to the …