Magnetic field induced dielectric relaxation in the strain glass state of Pr0.6Ca0.4MnO3

Abstract

We present the dielectric and magnetodielectric properties of Pr0.6Ca0.4MnO3 polycrystalline sample. Dielectric permittivity ({\epsilon'}) (and d{\epsilon'}/dT) portrays the charge order and other magnetic transitions observed in the magnetization measurement. Dielectric study has revealed a relaxation corresponding to ordering of polarons ~ 60 K that follows Arrhenius behaviour both in the presence and absence of magnetic field and another relaxation was noticed ~ 30 K only under a critical magnetic field (3.2 T) that shows critical slow down of electronic charges obeying power law. Further, the magnetic field induced relaxation shifts to low temperatures with the increase of magnetic field. The observed field induced dielectric relaxation below the reentered charge ordered state is linked with the rapid motions of boundaries of the coexisting phases towards the martensite phase transformation.