Wave reversion mode stability as a function of diameter and wall thickness for permalloy and nickel nanotubes.

• Non-monotonic coercivity and remanence as a function of diameter for Py and Ni NTs. • Wave reversal mode could be identified by the area enclosed in the hysteresis curve. • New phase diagram allows determining the stability of the wave reversal mode. The wave reversal mode is a magnetization reversal mechanism that appears in ferromagnetic nanotubes of certain geometric parameters when an external magnetic field is applied perpendicular to their axes. The distinctive feature of this mode is that leads to well-defined S-shaped hysteresis curves. In order to gain insight into the stability of this latter effect, we have performed micromagnetic simulations for permalloy and nickel nanotubes obtaining a non-monotonic behavior for coercivity as well as for remanence as a function of nanotube diameter for both materials. Motivated on these latter intriguing results, we found that measuring the area that encloses the hysteresis curve is a novel and simple strategy to identify the appearance of the wave reversal mode. An additional contribution of this work is the proposal of a new magnetic phase diagram that allows determining the stability of this reversal mechanism as a function of the geometric and magnetic parameters of the tubes. [ABSTRACT FROM AUTHOR]