Half-metallic double perovskite oxides: recent developments and future perspectives

Abstract

The continuous miniaturization of charge-based electronic devices and overcoming the bottleneck of Moore's law have driven the rapid growth of spintronics, spintronics operates the freedom of electronic spin rather than the charge to transmit, process, and store information. To develop spintronic devices with high performance, half-metallic (HM) materials with carriers with 100% spin polarizability are highly required. Double perovskite (DP) oxides stand out among the possible new HM spintronic materials owing to their good structural and compositional flexibilities as well as stable ferromagnetism above room temperature and large spin polarization. Over the past decade, numerous HM DP oxides have been theoretically predicted by first-principles calculations; however, only a handful have been experimentally verified. This article presents a comprehensive review on the recent progress of HM DP oxides from theoretical and experimental aspects. The primary focus is on first-principles investigations of HM DP oxides and some representative experimental data measured from HM DP oxides in the forms of single crystals (or bulks), thin films, and nanoparticles. Their synthesis methods and structural characterization techniques are described, and their versatile applications in the fields of magnetic tunnel junctions, spin filters, field effect transistors, Josephson junctions, electrocatalysts, and solid oxide fuel cells are also discussed. Finally, we give some perspectives on the future research studies of HM DP oxides and highlight some important issues that need to be addressed in the near future.