The behavior of magnetostrictive nanowires and their potential for use in the design of devices for actuation and sensing applications is explored in this chapter. An introduction to magnetostrictive materials is presented first. This includes MOKE images of the response of magnetic domains in a magnetostrictive material to applied magnetic fields and to applied mechanical compression, as well as presentation of typical sensor and actuator characterization data from bulk samples of the magnetostrictive alloy Fe100−xGax (10 ≤ x ≤ ~35 atomic %) (also known as Galfenol or Fe-Ga). Next, models of magnetostriction at the macro- and microscale are presented. Micromagnetic simulations are used to visualize the significant role of shape anisotropy on magnetostriction in nanowires and to explain the challenges associated with achieving magnetic domain rotation in high aspect ratio nanowires. Methods for fabrication of Fe-Ga nanowires and Fe-Ga/X multilayer nanowires are discussed. Structural and magnetic characterization data are presented from Fe-Ga and Fe-Ga/Cu nanowires with of diameters of 100–200 nm and aspect ratios ranging from as low as 0.5 in some of the multilayer nanowire segments to over 100 in Fe-Ga single alloy nanowires. The last two sections of the chapter present experimental studies into use of the nanowires for actuation and sensing. This includes demonstration of magnetic domain rotation and magnetostriction in Fe-Ga/Cu multilayer nanowires in response to an applied magnetic field, as well as the use of a GMR sensor to detect magnetic domain rotation in response to application of a compressive mechanical load to an array of Fe-Ga/Cu nanowires.
|Original language||English (US)|
|Title of host publication||Magnetic Nano- and Microwires|
|Subtitle of host publication||Design, Synthesis, Properties and Applications|
|Number of pages||40|
|State||Published - Jan 1 2020|
Bibliographical notePublisher Copyright:
© 2020 Elsevier Ltd. All rights reserved.
- Magnetostrictive alloys
- Multilayer nanowires
- Shape anisotropy
- Vortex domains