Large Magnetization and Frustration Switching of Magnetoresistance in the Double‐Perovskite Ferrimagnet Mn2FeReO6. (26th August 2015)

• Record Type: Journal Article
• Authors: Arévalo‐López, Angel M.; McNally, Graham M.; Attfield, J. Paul
• Is Part Of: Angewandte Chemie. Volume 127:Number 41(2015)
• Page Start: 12242
• Page End: 12245
• Publication Date: 2015-08-26
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201506540
• Languages: English
• ISSNs: 0044-8249

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Ferrimagnetic A₂BB′O₆ double perovskites, such as Sr₂FeMoO₆, are important spin‐polarized conductors. Introducing transition metals at the A‐sites offers new possibilities to increase magnetization and tune magnetoresistance. Herein we report a ferrimagnetic double perovskite, Mn₂FeReO₆, synthesized at high pressure which has a high Curie temperature of 520 K and magnetizations of up to 5.0 μ_B which greatly exceed those for other double perovskite ferrimagnets. A novel switching transition is discovered at 75 K where magnetoresistance changes from conventional negative tunneling behavior to large positive values, up to 265 % at 7 T and 20 K. Neutron diffraction shows that the switch is driven by magnetic frustration from antiferromagnetic Mn²⁺ spin ordering which cants Fe³⁺ and Re⁵⁺ spins and reduces spin‐polarization. Ferrimagnetic double perovskites based on A‐site Mn²⁺ thus offer new opportunities to enhance magnetization and control magnetoresistance in spintronic materials.</p> </abstract>