Layer-selective detection of magnetization directions from two layers of antiferromagnetically-coupled magnetizations by ferromagnetic resonance using a spin-torque oscillator

•Magnetization states of 2 recording layers (RLs) are detected layer-selectively.•A spin-torque oscillator (STO) is used as a read device.•The STO induces and detects state-dependent ferromagnetic resonance (FMR) in each RL.•The RLs are designed to suppress interlayer interference caused by dipolar fields.•The changes in STO oscillation occur on a 1-ns timescale shown by moving the STO.