Magnetization switching in a garnet thin film

An improved technique for observing subnanosecond magnetization changes in thin films has been used to study the underdamped oscillatory behavior in a (Y
2.5
Gd
0.5
) (Fe
4
Ga
1
)O
12
sample. The measurement setup uses a version of the alternate sampling technique in which the sensitivity has been upgraded by the use of a lock-in amplifier. By using a shorted stripline of appropriate length to apply to the film two properly timed magnetic field steps, the precession of the magnetization can be quelled, and the magnetization can be switched between initial and final directions in a half-cycle of the resonant frequency.