Cd 2 FeReO 6 : A High- T C Double Perovskite Oxide with Remarkable Tunneling Magnetoresistance.

In this study, we successfully synthesized the double perovskite oxide Cd 2 FeReO 6 by using a high-temperature and high-pressure method. The crystal structure was confirmed to belong to the P 2 1 / n space group, exhibiting approximately 68% ordering of Fe 3+ and Re 5+ ions at the perovskite B-site with the remaining regions showing antisite disorder. The measured Curie temperature of Cd 2 FeReO 6 was 460 K, slightly lower than expected but still significantly above room temperature. Remarkably, Cd 2 FeReO 6 displayed a remarkable low-field butterfly type tunneling magnetoresistance of -23% (-37% between the lowest and the largest values) at 5 K and 90 kOe, the highest among the A 2 FeReO 6 ( A = Ca, Sr, Pb, Ba) family. First-principles calculations provided insight into the origin of this observed magnetoresistance behavior, revealing Cd 2 FeReO 6 's half-metallic ferrimagnetic nature. This research extends our understanding of the double perovskite family and emphasizes its potential significance in the domains of spintronics and materials science. The exploration of differing magnetoresistance behaviors between Cd 2 FeReO 6 and Ca 2 FeReO 6 , along with the influence of antisite disorder in Cd 2 FeReO 6 , opens intriguing avenues for further research.