The development of near-room-temperature magnetic refrigeration relies on magnetic materials with large entropy changes and broad operating ranges. Here, we report an interface functionalization strategy to construct La 0.67 Ca 0.33 MnO 3 @ZIF-67 composites via in-situ growth method. The introduction of ZIF-67 increased the specific surface area and created abundant mesopores. The composite with low ZIF-67 content (La 0.67 Ca 0.33 MnO 3 @ZIF-67-1) showed an enhanced maximum magnetic entropy change (3.66 J·kg -1 ·K -1 ) and relative cooling power (251.8 J·kg -1 ) under 5 T compared to the pure La 0.67 Ca 0.33 MnO 3 . However, higher ZIF-67 loading degraded magnetocaloric performance due to the dilution effect of the non-magnetic phase. Notably, critical behavior analysis revealed a shift from the Ising model in pure La 0.67 Ca 0.33 MnO 3 , indicative of short-range interactions, to the mean-field model in composites, dominated by long-range interactions. This indicated that ZIF-67 suppressed critical magnetic fluctuations through interfacial coupling and physical isolation. This study confirmed that interfacial regulation using non-magnetic porous metal-organic frameworks (MOFs) is an effective approach for optimizing the magnetocaloric properties of perovskite manganites and modulating their phase transition behaviors.
Zhang et al. (Thu,) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: