The effects of EMI from cell phones on GMR magnetic recording heads and test equipment

In this work, we study the effects of electromagnetic interference (EMI) on GMR heads and test equipment. It was found that three types of cell phones (AMPS, TDMA and CDMA) did not cause magnetic or resistance change damage to the GMR heads, such as that caused by nearby ESD events. It was also found that EMI from a TDMA cell phone caused errors in a spin stand tester that could disrupt the test process and create yield losses in production. It is concluded that it may be prudent to restrict operation of mobile phones in the immediate proximity of GMR heads during handling and testing.