Spin torque transistor revisited

We theoretically study the operation of a 4-terminal device consisting of two lateral thin-film spin valves that are coupled by a magnetic insulator such as yttrium iron garnet via the spin transfer torque. By magnetoelectronic circuit theory we calculate the current voltage characteristics and find negative differential resistance and differential gain in a large region of parameter space. We demonstrate that functionality is preserved when the control spin valve is replaced by a normal metal film with a large spin Hall angle. (C) 2013 AIP Publishing LLC.