Here, we report the influence of Jahn-Teller active Cu substitution on the charge-ordering characteristics of one of the well-known manganite Pr0.45Sr0.55MnO3(S55) which exhibits distorted tetragonal structure (I4/mcmsymmetry).Magnetization studies reveal that S55 exhibitsferromagnetic (FM) ordering with Curie temperature, TC ~220.5 K, antiferromagnetic (AFM) ordering below the Néel temperature TN~ 207.6 K, and charge-ordering (CO) transition TCO~ 210 K which are in-line with the specific heat CP(T) data. Below TN, the CO (Mn3+↔ Mn4+) induces long-range AFM order, whereas above TNthe FM-ordering driven by the double exchange (DE) interaction leads to a mixed-phase of competing CO-AFM and DE interaction in the region TN< T < TCO, and dominates completely over CO for T > TCO. However, the robust charge-ordering state breakdown altogether with a dilute substitution of Cu at the Mn B-sites resulting in enhanced ferrimagnetic order with TFN~ 273 K, yet showing large magnetocrystalline anisotropy as confirmed by the ferromagnetic resonance (FMR)studies. Our results reveal that S55 possesses the cationic distribution: (Pr3+Sr2+)A[Mn3+Mn4+]BO3different from the Cu substituted system: (Pr3+Sr2+)A[Cu2+Mn3+Mn4+]BO3which is responsible for its diverse magnetic structure metamagnetic transition (HT-Max~ 8.85 kOe at 180 K) associated with the CO phenomena in S55, first-order nature of the TCO, and the heat capacity (CM= A (T - TN)-α) critical exponent α = 0.097 (0.154) in the region T > TN(T < TN) are consistent with the magnetic structure. The temperature dependence of FMR resonance field ΔHRes(T), peak-to-peak width HPP(T) and Gilbert damping factor αG(T) shows clear anomalies across the TCOand in the morphotropic region (AFM/CO/FM) signifying the important role of admixtured (3+/4+) Mn state. A strong correlation between the FMR αG(T) and switchable magnetic entropy change (∆SMax~ ‒ 8/+3 J kg-1K-1for ∆H = 90 kOe) has been established.
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