An optically active spiral

Multiferroics The material cupric oxide exhibits magnetoelectric coupling, meaning that its magnetic properties can be controlled by electric fields. In its spin spiral phase, cupric oxide has a spiral magnetic ordering that can be right- or left-handed. Masuda et al. used electric fields to create purely left- or right-handed samples and then studied their optical activity. The samples exhibited natural optical activity, which the researchers were then able to control with electric fields. Science , this issue p. [496][1] [1]: /lookup/doi/10.1126/science.aaz4312