A Review on the Magnetic Behaviour of Ni and Mn based Double Perovskites

Abstract

This review article describes the observation of some fascinating phenomena in double perovskites. Multifunctional double perovskite materials of general formula A2BB'O6 have received significant scientific attention owing to their fascinating physical characteristics, such as low field magnetoresistance, high temperature ferromagnetism, metal-insulator transition, spin ordering, phase separation and multiferroicity making them a potential candidate for spintronics device applications. Among them, R2NiMnO6 double perovskites have drawn significant attention in last few decades, owing to their rich physics and potential applications. The ordered arrangement of B-site cations is essential for unlocking unique magnetic and transport characteristics in these compounds. While double perovskites with ordered B-sites are highly sought after for their magnetoresistive and ferromagnetic (FM) properties, achieving perfect order is challenging due to the similarity in ionic radii and oxidation states among various cations at the B-site, leading to randomness in the arrangement of ions. This results in the occurrence of "anti-site" disorders, where the arrangement becomes random. These disorders may manifest as Ni2+-O–Ni2+ and Mn4+–O–Mn4+ configurations, causing antiferromagnetic (AFM) interactions in R2NiMnO6. Furthermore, the development of antiphase boundaries (APBs) owing to anti-site disorders may be the primary source of antiferromagnetic interaction in R2NiMnO6. These antisite disorders strongly affect the properties of the double perovskites and lead to the origination of some fascinating phenomena such as exchange bias and spin glass. These phenomena are utilized in the development of spintronic devices. The discussion made in the present review article would be extremely helpful to the researchers who are doing research in the field of material science.