Charge-ordering breakdown dynamics and ferromagnetic resonance studies ofB-site Cu diluted Pr_1‒xSr_xMnO₃

Here, we report the influence of Jahn-Teller active Cu substitution on the charge-ordering (CO) characteristics of one of the well-known manganite Pr_0.45Sr_0.55MnO₃(S55) with a distorted tetragonal structure. Magnetization studies unveil a complex magnetic phase diagram for S55, showing distinct temperature ranges corresponding to various magnetic phases: a ferromagnetic phase dominated by the Double Exchange interaction withT_C∼ 220.5 K, an antiferromagnetic phase belowT_N∼ 207.6 K induced by CO with a transition temperature ofT_CO∼ 210 K consistent with the specific heatC_P(T) data, and a mixed phase in the rangeT_N<T<T_COdue to the competitive interplay of these two interactions. Dilute substitution of Cu at the MnB-sites disrupts the robust charge-ordered state, leading to enhanced ferrimagnetic order withT_FN∼273 K and significant magnetocrystalline anisotropy as confirmed by ferromagnetic resonance (FMR) studies. The Cu-substituted system displays a distinct cationic distribution compared to the pristine S55, contributing to its diverse magnetic structure. Our findings also reveal the irreversible metamagnetic transition (H_T-Max∼ 8.85 kOe at 180 K) associated with the CO phenomena in S55 and the first-order nature of the phase transition acrossT_CO. The magnetic heat capacity critical analysis (C_Mag=A(T-T_N)^-α) yields the exponent,α=0.097 (0.154) in the regionT>T_N(T<T_N) consistent with the magnetic structure. The temperature dependence of FMR resonance field ΔH_Res(T), peak-to-peak widthH_PP(T), and Gilbert damping factorα_G(T) show clear anomalies across the magnetic transitions signifying the important role of admixtured (3+/4+) electronic state of Mn. Additionally, a strong correlation between the FMRα_G(T) and switchable magnetic entropy change (ΔS_Max∼-8/+ 3 J kg^-1K^-1forΔH=90 kOe) has also been established in S55.