Giant magnetoimpedance in twisted amorphous CoP multilayers electrodeposited onto Cu wires

CoP multilayers grown over Cu wires exhibit magnetoimpedance phenomenon. The change in the real part of the measured voltage is V-R = [V(H = 0 Oe)-V(H-max)]/V(H-max) approximate to 3300%(I-rms = 500 mA, 90 kHz); the maximum dV(R)/dH, is 1280%/Oe at H-DC = 1.2 Oe. These quantities are enhanced if the wire is subjected to an angular deformation by means of a torque applied to the wire; V-R approximate to 7000% and dV(R)/dH approximate to 2400%/Oe, are found at 9 and 1.2 Oe, respectively, for a 90 degrees twisted sample, produced by the change in the magnetic anisotropy direction, from the longitudinal to the helical one. (C) 1999 Published by Elsevier Science B.V. All rights reserved.