Wave reversal mode: A new magnetization reversal mechanism in magnetic nanotubes

SOFÍA RAVIOLO; DIANA M. ARCINIEGAS JAIMES; NOELIA BAJALES; JUAN ESCRIG

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2020

0304-8853

e have investigated the magnetic properties of 14 nm thick and 1μm long nickel and permalloy nanotubes withexternal diameters of 40 and 100 nm as a function of the angleθat which the external magneticfield is applied.Our results show that the coercivity of 40 nm diameter nickel nanotubes follows a non-monotonic behavior fromθ=0°uptoθ= 60°, while that corresponding to permalloy displays an increasing monotonic trend at the sameangular range. Atθ= 90°, both materials evidence a sharp drop of the coercivity to zero, indicating that thereversal mechanism has changed to a pseudo-coherent rotation. On the other hand, nickel and permalloy na-notubes with 100 nm in diameter exhibit a similar angular dependence of the coercivity, reversing their mag-netization through the nucleation and propagation of vortex domain walls for angles lower than 75°. Forθ= 90°,a novel striking mechanism, the wave reversal mode (W), arises. This phenomenon leads to an unusual S-typesh