Quantitative Calculation of the Clustering Behavior of Fe‐Rich and Cr‐Rich REFe_pCr_1−pO₃ Crystals

Abstract

This work has focused on the cluster state of B‐site ions in the rare‐earth perovskite REFepCr1−pO3, and GdFe0.5Cr0.5O3 is taken for instance. This analysis indicates a paramagnetic behavior of the system, which originates from the paramagnetic contribution of the Gd3+. An internal‐field model is used to simplify the superexchange interaction between the A/B‐sites. Furthermore, the cluster state of B‐site ions is computed using the average number of nearest‐neighborhoods. Using Marine Predator Algorithm to fit the experiment data, it is found that Fe–Cr interaction does not conform to the case of ferromagnetic superexchange; therefore, there is no spin glass behavior in this system. Via fitting the Mossbauer spectrum at low temperatures (120 and 12 K), the calculations described above are verified. The calculation gives the hyperfine‐field intervals of 2.47 and 0.92 T at 120 and 12 K. It is found that B‐site ions tend to form clusters. The arrangement of the ions is random and without the tendency of orderly interval occupation of ions (like double perovskite). The study sheds light on the mechanism of single‐ion clustering and introduces new methods for calculating single‐ion clustering states. It can also be applied to the case of other A‐site ions in perovskite system and is not just limited to p = 0.5 in REBpB’1−pO3.

Effect of Annealing Temperature on the Magnetization Behavior of LaFe0.5Cr0.5O3

“…To support our viewpoint, we have employed a Monte Carlo simulation of the Heisenberg model and utilized the particle swarm optimization algorithm to t disordered systems' parameters (x,y) [27]. These two parameters have detailed explanations in our previous work [28,29]. The Heisenberg Hamilton is : where < i,j > represents the nearest neighbor of i site, J ij is the exchange constant of i and j site, h is the magnetic eld actions on the z-axis, and S z refers to the projection of spin on the z-axis.…”