Slow Relaxation of Magnetic Susceptibility in Polycrystalline GdBaCo2O5.53 above the Curie Point and the Effect of High Hydrostatic Pressures

A slowly decaying anomaly of magnetic susceptibility (characteristic time τ ~ 103 s) is revealed in studying the ferromagnetic–paramagnetic phase transition in polycrystalline cobaltite GdBaCo2O5.53 that occurs due to the remaining short-range magnetic order at temperatures above the Curie point (TC = 275 K). High hydrostatic pressures (up to 1.48 GPa) are found to have a weak effect on TC with baric coefficient dTC/dP = 2.1 K/GPa.