Are these sentences grammatically correct?? How to correct?

"Control of magnetic multidomain states is a central challenge in developing multilevel spintronic devices. Due to the random domain nucleation process, it is hard to be achieved in a normal ferromagnet.", "We demonstrate that both traditional spin transfer torque and spin-orbit torque play the essential roles in the controllable domain nucleation.", and this one "Compared with previous reports that the magnetization can only be switched between two uniformly magnetized states, we show that the current induced magnetization switching can be achieved between any two multidomain sates.". The referee says that these sentences are grammatically incorrect, but i cannot find. Thanks a lot.