Toward Wafer Scale Inductive Characterization of Spin-Transfer Torque Critical Current Density of Magnetic Tunnel Junction Stacks

We explore the prospects of wafer-scale inductive probing of the critical current density $j^{\rm c}{^{0}} $ for spin-transfer torque (STT) switching of CoFeB/MgO/CoFeB magnetic tunnel junctions with varying MgO thickness. From inductive measurements, magnetostatic parameters and effective damping are derived and $j^{\rm c0}$ is calculated based on STT equations. The inductive values compare well with the values derived from current-induced switching measurements on individual nanopillars. Using a wafer-scale inductive probe head could enable wafer probe station-based metrology of $j^{\rm c0}$ in the future.