For the last two decades, magnetic tunnel junctions (MTJs) have played a central role in spintronic devices such as read heads of hard disk drives and nonvolatile magnetoresistive random access memories (MRAMs), and researchers are constantly working to improve their performance. One of the most prominent achievements that accelerated the technology’s practical applications was the realization of giant tunnel magnetoresistance (TMR) ratios by using rock-salt type MgO crystalline barrier. Now, in an article appearing in this week’s issue of Applied Physics Letters, a Japanese team of researchers has succeeded in applying MgGa2O4 to a tunnel barrier, the core part of an MTJ, as an alternative material to more conventional insulators such as MgO and MgAl2O4.