All-in-all-out magnetic domains: X-ray diffraction imaging and magnetic field control

Long-range noncollinear all-in-all-out magnetic order has been directly observed for the first time in real space in the pyrochlore Cd2Os2O7 using resonant magnetic microdiffraction at the Os L3 edge. Two different antiferromagnetic domains related by time-reversal symmetry could be distinguished and have been mapped within the same single crystal. The two types of domains are akin to magnetic twins and were expected - yet unobserved so far - in the all-in-all-out model. Even though the magnetic domains are antiferromagnetic, we show that their distribution can be controlled using a magnetic field-cooling procedure.