MAGNETOMECHANICAL EFFECT IN NICKEL AND COBALT

The change in magnetization as a result of applied uniaxial stress has been measured in nickel and cobalt. Both tensile and compressive stre sses were applied up to 125 MPa. Magnetostriction and anhysteretic mag netization as a function of stress were also measured. The change in m agnetization with stress depended on the applied stress and the displa cement between the prevailing magnetization and anhysteretic. At the l oop tips, nickel showed a +6 mT (compression) and -6 mT (tension) magn etization change while cobalt displayed a +15 mT (compression) and -15 mT (tension) magnetization change. At remanence, nickel decreased in magnetization by 45 mT under either sign of stress, while cobalt decre ased by 20 mT also under either sign of stress. Magnetomechanical chan ges in magnetization near the loop tips were mostly reversible, while at remanence the magnetomechanical change was predominately irreversib le. Cobalt generally displayed larger changes in magnetization with st ress than nickel at locations close to the loop tips, while the conver se was true at locations near remanence. The results confirm the hypot hesis that the magnetomechanical effect (dM/d sigma) depends on the di splacement between the anhysteretic and prevailing magnetization. (C) 1997 American Institute of Physics.