Phase coexistence and magnetocaloric effect inLa5/8−yPryCa3/8MnO3(y=0.275)

The magnetocaloric effect (MCE) was measured to probe the nature of phase coexistence of structurally different ferromagnetic metallic (FMM) and charge-ordered insulating phases in ${\text{La}}_{5/8\ensuremath{-}y}{\text{Pr}}_{y}{\text{Ca}}_{3/8}{\text{MnO}}_{3}$ $(y=0.275)$ single crystals. The MCE peaks with both positive and negative values are observed in the vicinity of the multiple-phase transitions in the system. Strain associated with the phase coexistence has been known to stabilize a strain-glass state as well as a strain-liquid state. The large MCE is observed in the ``dynamic'' strain liquid state, while it is relatively small in the ``frozen'' strain-glass state. The MCE data reveal that the sharp increase in the magnetization below the Curie temperature in the strain-liquid region is attributed to the enhancement of the FM domain regions that are already present in the material. MCE is also shown to be a useful method to probe the subtle balance of coexisting phases in mixed-phase manganites.