Abstract
An abnormal reproduced waveform was observed in spin-valve (SV) heads. We show that this abnormal wave-form was caused by instability of the pinned-layer magnetization even below the blocking temperature (Tb). In SV heads with an NiO/CoO-bilayer (NiO/CoO-SV heads), the pinned-layer magnetization is easily aligned to the track width direction and becomes unstable even at room temperature. FeMn-SV heads showed a relatively stable wave-form, in contrast to NiO/CoO-SV heads. However, below a temperature of 100°C, the pinned-layer magnetization reverses and is pinned easily to the direction of the applied current field. On the other hand, the pinned-layer magnetization in NiMn-SV heads is highly stable, mainly because of the high Tb.
