Chinese Phys. Lett . 43 020713)"> Domain imaging: MOKE microscopy imaging of altermagnetic domains in haematite. Images a and c show the domains themselves, while b and d show the MOKE signal when a square-wave magnetic field is applied to the material. (Courtesy: Chinese Phys. Lett . 43 020713) Researchers in China have developed a new way of probing the magnetic domains within altermagnetic materials and used it to study a prominent altermagnet candidate, alpha-phase iron oxide. According to their measurements, this material shares certain properties with ferromagnets despite having a near-zero net magnetization – a fact the researchers say supports its classification as an altermagnet. In most magnetically ordered materials, the spins of atoms (that is, their magnetic moments) can either line up parallel with each other or antiparallel, alternating up and down.…