Negative magnetization in the medium-entropy Pr_1/3Dy_1/3Ho_1/3CrO₃ and PrCrO₃ ceramics: comparative crystal structure, optic, dielectric and magnetic properties

In recent years, raising investigation activity in entropy-stabilized ceramic oxides has been driven by their innovative approach to designing a thermodynamically stable multi-element system, which provides a new focus on investigating complex functional materials. Especially, complex and singular physical properties of orthochromite have generated rising research in recent years. Of this family, the PrCrO₃, DyCrO₃, and HoCrO₃ systems are particularly interesting since, below Néel temperature (T_N), they present negative magnetization in the ZFC mode. Here, we have employed this approach and designed a medium-entropy (MECs) Pr_1/3Dy_1/3Ho_1/3CrO₃ (PDH) ceramic to study not only whether the magnetic characteristics prevail, but also the state of optical and dielectric properties of this new compound. In addition, the physical properties studied were compared with the single PrCrO₃ (PC) compound. These compounds were synthesized through a facile combustion synthesis route. The X-ray diffraction analysis, energy-dispersive X-ray spectroscopy (EDS), and surface scanning elemental mapping reveal that a single phase is stabilized and equimolar cations are homogeneously distributed in the PDH-MECs. We found that the disorder of cations in the A-site of the structure has no significant effect on the optical transition in the visible electromagnetic region and dielectric properties with respect to the simple compound PC. In contrast, the magnetic properties are strongly affected in the MECs-PDH compound. We found that the T_N is tuned through the O–Cr–O angles and below the antiferromagnetic transition. The results suggest that the negative magnetization in the ZFC mode is an intrinsic feature in these compounds since the negative ZFC susceptibility below T_N predominates despite the cationic disorder. Furthermore, their negative magnetic mechanism in both the MECs-PDH and PC compounds are discussed in terms of the Γ₂(F_xC_yG_z) magnetic configuration. Graphical abstract: [Figure not available: see fulltext.]