Stress-magnetic effects in iron-rich amorphous alloys and shock-stress sensors with no power

Sensitive stress-magnetic effects are presented for micro-crystallized iron-rich amorphous ribbons, in which the maximum permeability shows an approximate 15-fold change when applying a tensile stress of 10 kg/mm2parallel to the ribbon length. Micro-crystallizing heat treatments by anneal and quench improve not only the stress sensitivity but also the magnetic stability of the ribbon in which the value of the coercivity is very constant through an acceleration test of 150°C, 300 hours. A sensitive shock stress sensor with no power which can detect a shock as small as a 6 g drop from 5 mm height and is applicable for use as a knock sensor or an oscillation sensor is also represented using the stress-magnetic effect.