Bordoloi A, Jena S K, Tiwari P, Datta A, Weise B, Medwal R, Rawat R S, Thota S
Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.
Leibniz-IFW Dresden, Institute for Complex Materials, D-01069 Dresden, Germany.
J Phys Condens Matter. 2024 Apr 25;36(29). doi: 10.1088/1361-648X/ad3c04.
Here, we report the influence of Jahn-Teller active Cu substitution on the charge-ordering (CO) characteristics of one of the well-known manganite PrSrMnO(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 with∼ 220.5 K, an antiferromagnetic phase below∼ 207.6 K induced by CO with a transition temperature of∼ 210 K consistent with the specific heat(T) data, and a mixed phase in the range<<due to the competitive interplay of these two interactions. Dilute substitution of Cu at the Mn-sites disrupts the robust charge-ordered state, leading to enhanced ferrimagnetic order with∼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 (∼ 8.85 kOe at 180 K) associated with the CO phenomena in S55 and the first-order nature of the phase transition across. The magnetic heat capacity critical analysis ((-)) yields the exponent,0.097 (0.154) in the region>(<) consistent with the magnetic structure. The temperature dependence of FMR resonance field Δ(), peak-to-peak width(), and Gilbert damping factor() 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 FMR(T) and switchable magnetic entropy change (-8/+ 3 J kgKfor90 kOe) has also been established in S55.
在此，我们报道了 Jahn-Teller 活性 Cu 取代对具有扭曲四方结构的著名锰酸盐 PrSrMnO(S55) 的电荷有序 (CO) 特性的影响。磁化研究揭示了 S55 复杂的磁相图，显示出对应于各种磁相的不同温度范围：在约 220.5 K 时由双交换相互作用主导的铁磁相，在约 207.6 K 以下由 CO 诱导的反铁磁相，其转变温度约为 210 K，与比热 (T) 数据一致，以及由于这两种相互作用的竞争相互作用而在该范围内的混合相。在 Mn 位点上稀释取代 Cu 会破坏稳健的电荷有序状态，导致在约 273 K 时增强的亚铁磁有序和显著的磁晶各向异性，这已通过铁磁共振 (FMR) 研究得到证实。与原始的 S55 相比，Cu 取代体系显示出独特的阳离子分布，这有助于其多样的磁结构。我们的研究结果还揭示了与 S55 中的 CO 现象相关的不可逆变磁转变（在 180 K 时约为 8.85 kOe）以及相变的一级性质。磁热容量临界分析 ((-)) 在区域 (>) 中产生指数 0.097 (0.154)，与磁结构一致。FMR 共振场 Δ()、峰峰宽度 () 和吉尔伯特阻尼因子 () 的温度依赖性在磁转变过程中显示出明显的异常，这表明 Mn 的混合 (3+/4+) 电子态起着重要作用。此外，在 S55 中还建立了 FMR(T) 与可切换磁熵变（90 kOe 时为 -8/+ 3 J kgK）之间的强相关性。
