Re-entrant spin freezing behavior in La0.85Ca0.15Mn0.95Fe0.05O3 manganite

Abstract The effects of partially replacing Mn with Fe ions in the La 0.85 Ca 0.15 MnO 3 system are reported. On replacing 5% of the Mn with Fe ions the system exhibits a transition to a re-entrant spin glass like phase with a ferromagnetic transition at 170 K and spin freezing transition at T ∼100 K. The system remains insulating throughout both the ferromagnetic and glassy phases with however a sharp resistivity increase at low temperature ( T ∼150 K). The spin freezing temperature shifts upwards with increasing frequency and magnetic relaxation effects are observed. However conventional spin glass features such as a memory effect are not observed and the spin freezing temperature is relatively insensitive to applied magnetic fields.