Pressure tuning of double exchange in 3d-5d double perovskite Sr2FeOsO6

We demonstrate that compression of Sr2FeOsO6, a double perovskite structure with an ordered crystalline arrangement of iron (3d) and osmium (5d) transition metal ions, allows for continuous and reversible control of magnetic coercivity and saturation magnetization. The effect leverages the tunability of crystal electric fields with pressure to alter Fe-O-Os magnetic exchange interactions and transform a material with an otherwise mute response to magnetic fields into one with coercive field typical of robust permanent magnets.