Abstract
We report a method that can be used to study the cooling effect on the thermal actuator of a flying slider with greater sensitivity than magnetoresistive ( MR ) sensor measurements. By monitoring the first and second harmonics of the read back signal associated with the ac excited thermal protrusion, the second harmonic signal diverges from the linear first harmonic signal as cooling effect intensifies. This is attributed to distortion of the read back signal envelope with increased cooling. Results also indicate that a bonded lube disk produces a higher cooling effect compared with a bonded+ mobile lube disk. These were correlated with MR sensor temperature measurements. An ANSYS simulation model was developed to explain the nonlinearity in the second harmonic.