EXPERIMENTAL STUDIES ON Mn-DOPED COBALTITES: Pr0.6Sr0.4Co1-yMnyO3 (0 = y = 1)

Abstract

Both Pr0.6Sr0.4MnO3 and Pr0.6Sr0.4CoO3 are ferromagnetic (FM) metals below TC = 305 and 214 K, respectively. The long-range ferromagnetism as well as metallicity in Pr0.6Sr0.4CoO3 is strongly destabilized with Mn substitution and complex inhomogeneous magnetic ground state evolves in the nominally doped compounds as a result of competing magnetic interactions. Magnetoresistance at low temperatures increases dramatically upon Mn substitution which is basically due to spin dependent tunneling between neighboring FM clusters. The intermediate compounds (0.3y5) of Pr0.6Sr0.4Co1-yMnyO3 are highly insulating at low temperatures and exhibit Debye-like Dielectric relaxation. They also show large magneto-dielectric effect (MDE) at low temperatures which was attributed to dynamic spin dependent tunneling. Since the low and heavily Mn doped compounds (y = 0.1-0.25 and 0.7-0.9) exhibit huge MR and intermediate compounds (y = 0.3-0.5) show large MDE at low temperatures, the Mn doped samples are potential candidates for low temperature based magnetic field sensor applications.