Electromagnetic field induced degradation of magnetic recording heads in a GTEM cell

A gigahertz transverse electromagnetic mode (GTEM) cell was used to apply a controlled RF electric field to magnetic recording assemblies. The resistance and magnetic properties of the giant magnetoresistive (GMR) and tunneling MR (TMR) sensors were measured before and after exposure to the electric field. No degradation in GMR sensor properties was observed for pulsed field strengths up to 40 V/m for the standard assembly configuration. However, severe resistance and magnetic damage was observed when an additional 7 cm long wire was attached to the input of the GMR sensor. It is concluded that it is important to understand and measure the radiated immunity failure level for extremely ESD sensitive devices like magnetic recording assemblies.