Tuning magnetic anisotropy of amorphous CoFeB film by depositing on convex flexible substrates

Abstract

We have investigated the magnetic properties of amorphous Co40Fe40B20 (CoFeB) thin films grown on flexible polyimide (PI) substrates, which were fixed on convex molds with different curvatures during the magnetron sputtering deposition. When the flexible substrates were changed from convex to flat state after fabrication, a uniaxial magnetic anisotropy was induced in the CoFeB film due to magnetostrictive effect. Furthermore, the anisotropy also depends on the thicknesses of the film and substrate. Our results demonstrate a convenient method to tune the anisotropy of magnetic thin films grown on flexible substrates.

Anomalous Nernst effect in stressed magnetostrictive film grown onto flexible substrate

“…Films thinner than 5 nm usually exhibit strong perpendicular magnetic anisotropy (PMA) 28 , while the thicker ones commonly show in-plane magnetic anisotropy 29,30 . Moreover, due to its magnetostrictive properties, thick-CoFeB films have been grown onto flexible substrates, thus becoming essential systems to investigate the influence of the stress on the effective magnetic anisotropy 16,17 , as well as appearing as promising materials for application in flexible magnetic devices 31 , disposable electronics, smart cards, light-emitting diodes, wearable electronics and a broad range of sensors 18,32–35 .…”

Tuning magnetic anisotropy in Co–BaZrO3 vertically aligned nanocomposites for memory device integration

“…To this end, two approaches to improve tunnel junction performances for low energy and high frequency applications include adjusting the coercive eld of the ferromagnetic materials [12][13][14][15][16] and integrating anisotropic ferromagnetic lms. 17 In the second approach, various ferromagnetic materials, such as SmCo 5 , 18 CoFeB, [19][20][21] Fe-Pt, 22 and Pd/Co layered structures, 23 have been explored by using strain 24,25 and patterning 26 to achieve their anisotropic magnetic properties. For example, CoFeB and Fe-Pt [19][20][21][22] have shown anisotropic physical properties with certain thicknesses, while others 18,23 require numerous layers or patterning to achieve anisotropic magnetization.…”

Magnetization switching diagram of a perpendicular synthetic ferrimagnet CoFeB/Ta/CoFeB bilayer

“…Numerous reports on methods for inducing domain walls by electric current [ [15][16], manipulating them [ [17][18][19], and reversing polarity of perpendicularly polarized nanosized single-and multilayer magnets without external magnetic field [ 20 ] by means of local electric fields [ [21][22] and currents [ [23][24][25] ] can be found for single CoFeB magnets. However, magnetization reversal of multilayer magnetic structures remains a challenge due to a complicated game of anisotropy of layers [ [26][27][28][29][30], DMI interaction [ [31][32], tensile strains [ [33][34] and interlayer coupling [ [35][36]. The magnetic configurations present in in-plane antiferromagnetically exchange coupled bilayers, as well as bilayers with PMA, have been studied in the past [37][38][39].…”