Key Points London's "Financial Times" just reported on a new competitive threat to MP Materials. Minnesotan start-up Niron Magnetics says it can make better magnets out of common iron and nitrogen. Industry and government have contributed about $220 million in support to Niron so far. 10 stocks we like better than MP Materials › MP Materials (NYSE: MP) stock tumbled 9% through 3 p.m. ET Friday after London's Financial Times reported on a potential competitive threat to MP's vast investments (alrea ...