Evolution of magnetic and dielectric properties in Sr-substituted high-temperature multiferroic YBaCuFeO ₅

Abstract

We report the evolution of structural, magnetic and dielectric properties due\nto partial substitution of Ba by Sr in the high temperature multiferroic\nYBaCuFeO5. This compound exhibits ferroelectric and antiferromagnetic\ntransitions around 200 K and these two phenomena are presumed to be coupled\nwith each other. Our studies on magnetic and dielectric properties of the\nYBa1-xSrxCuFeO5 (x = 0.0, 0.25 and 0.5) show that substitution of Sr shifts\nmagnetic transition towards higher temperature whereas dielectric transition to\nlower temperature. These results points to the fact that magnetic and\ndielectric transitions get decoupled as a result of chemical pressure in form\nof Sr substitution. The nature of magnetodielectric coupling changes across the\nseries with the presence of higher order coupling terms. Additionally in these\ncompounds glassy dynamics of electric dipoles is observed at low temperatures.\n