Mazumdar Dipak, Das I
CMP Division, Saha Institute of Nuclear Physics, HBNI, 1/AF, Bidhannagar, Kolkata 700064, India.
Phys Chem Chem Phys. 2021 Mar 11;23(9):5596-5606. doi: 10.1039/d0cp06447e.
We have investigated the crystal structure and the nature of the magnetic ground state of the polycrystalline compound Pr2FeCrO6 (PFCO) through X-ray diffraction (XRD), magnetization, and magnetocaloric effect studies. Analysis of the XRD pattern reveals that the PFCO compound exhibits a B-site disordered orthorhombic crystal structure. The random distribution of Fe3+ and Cr3+ magnetic sublattices at the B-sites of the crystallographic unit cell helps to generate several fascinating magnetic properties. The compound exhibits three distinct anomalies in both the temperature dependence of the magnetization and the magnetic entropy change (-ΔS) curves, namely, (i) a G-type canted antiferromagnetic (AFM) ordering of the transition metal ions (TN1), (ii) a progressive spin reorientation (SR) transition (TSR), and (iii) an AFM ordering of Pr3+ sublattices at very low temperature (TN2). Surprisingly, a novel "diamagnetism-like" behavior appears in the low-temperature region for low applied field values. Moreover, we have also constructed the thermal evolution of the magnetic crystal structures in different transition regions with the help of irreducible representations of the crystal symmetry. Overall, our study of B-site disordered PFCO may help to encourage basic fundamental and applied research on disordered rare-earth and transition metal-based perovskite systems due to their interesting magnetic properties over a broad temperature range.
我们通过X射线衍射(XRD)、磁化和磁热效应研究,对多晶化合物Pr2FeCrO6(PFCO)的晶体结构和磁性基态性质进行了研究。XRD图谱分析表明,PFCO化合物呈现出B位无序的正交晶体结构。晶体学晶胞B位上Fe3+和Cr3+磁性亚晶格的随机分布有助于产生几种引人入胜的磁性。该化合物在磁化强度的温度依赖性和磁熵变(-ΔS)曲线中均表现出三个明显的异常,即:(i)过渡金属离子的G型倾斜反铁磁(AFM)有序化(TN1),(ii)渐进的自旋重取向(SR)转变(TSR),以及(iii)Pr3+亚晶格在极低温度下的AFM有序化(TN2)。令人惊讶的是,在低温区域,对于低外加场值出现了一种新颖的“类抗磁性”行为。此外,我们还借助晶体对称性的不可约表示构建了不同转变区域中磁性晶体结构的热演化。总体而言,我们对B位无序的PFCO的研究可能有助于推动对无序稀土和过渡金属基钙钛矿体系的基础基础研究和应用研究,因为它们在很宽的温度范围内具有有趣的磁性。