Observation of the multiple magnetic phases in double perovskite Pr1.8La0.2CoFeO6

The structural and magnetic properties of the double perovskite P r 1.8 L a 0.2 C o F e O 6 have been investigated. The X-ray diffraction study shows that the system acquires room-temperature orthorhombic phase with the Pnma space group. The X-ray photoemission spectroscopy (XPS) measurement confirmed that the B-site ions are present in mixed valence states i.e. Co has been found in Co ²⁺ and Co ³⁺ valance states whereas Fe has been found in Fe ³⁺/Fe ⁴⁺. Magnetic measurements of the system confirm the existence of several fascinating magnetic behaviors, such as long-range canted antiferromagnetism with T N ∼ 271 K, giant exchange bias, and re-entrant cluster glass phase ( T G ∼ 33 K). Field-dependent magnetization shows a large spontaneous exchange bias; H S E B ∼ 1.8 kOe and giant conventional exchange bias, H C E B ∼ 2.4 kOe at 5 K. Antiferromagnetic materials with large exchange bias can be utilized in high-density spintronic devices. Temperature-dependent Raman study demonstrates that the observed phonon mode exhibits anomalous behavior close to the magnetic transition temperature. Analysis of anomalous softening of phonon mode below T N , clarifies the presence of significant spin-phonon coupling while the magnetostriction effect does not play any significant role in the observed phonon anomaly.