At https://tallbloke.wordpress.com/2019/06/07/Earths-mantle-is-magnetic-res… … which is derived from www.upi.com/Science_News/2019/06/06/Earths-mantle-is-magnetic-researcher… … most scientists have thought in terms of the Earth's magnetism powered by materials in the core or crust. A new study published in the journal Nature differs. Hematite, a common iron oxide, retains it magnetic qualities even at very high temperatures. Hence, the Mantle is magnetic as well. Unsettled science is action.
See Nature (2019) DOI:10.1038/s41586–19-1254-8