Anomaly in the dielectric response at the charge-orbital-ordering transition of Pr 0.67 Ca 0.33 MnO 3

摘要: The complex impedance of a ${\mathrm{Pr}}_{0.67}{\mathrm{Ca}}_{0.33}{\mathrm{MnO}}_{3}$ crystal has been measured. frequency dependence is studied for wide range temperatures (50\char21{}403 K) and found to be characteristic relaxation process with single Debye time constant, which interpreted as dielectric constant the material. A strong peak observed in this (up ${10}^{6})$ at charge ordering transition suggesting an interpretation terms electric dipoles ${T}_{\mathrm{CO}}$ or term phase separation. Comparison ${\mathrm{Pr}}_{0.63}{\mathrm{Ca}}_{0.37}{\mathrm{MnO}}_{3}$\char22{}in separation much smaller absent\char22{}suggests between insulating metallic states.