On the Matteucci Effect and the Bistable Behavior in Microwires under Applied TorsionThe effects of an electrical current flowing through magnetic nanostructures are connected to several underlying novel phenomena that offer new opportunities for electronics technology or "spintronics." [1] For instance, spin-polarized current gives rise to the spin transfer-torque effect, in which the magnetization orientation in a magnetic layer of a tunnel junction or spin valve can be modified. In magnetic storage technologies, the design of writing and reading magnetic bits in high-speed devices profits of the effect induced by small current to inject domain walls (DWs), or to modify their motion characteristics (i.e., race track memories for magnetic storage or in logic devices). [2][3][4] Most of the studies have been conducted in Permalloy lithography nanostripes, where the shape determines the magnetic anisotropy characteristics. There, vortex and transverse DWs are injected or trapped in artificial notches or by local stray fields. [5,6] In cylindrical nanowires, the geometrical symmetry imposes significant differences. The motion of DWs was numerically solved using the Landau-Lifshitz-Gilbert equation, involving all different energy terms, where transverse or vortex DWs are, respectively, obtained for diameters smaller or larger than the exchange length of the corresponding material. [7] More recently, electrochemically grown cylindrical nanowires with diameter in the range 40-400 nm have been investigated experimentally and modeled by micromagnetic simulations. There, the magnetization reversal is typically activated by the propagation of a vortex DW which due to cylindrical geometry is also labeled as Bloch-point DW. [8,9] With the increase in diameter, as is the case of magnetic microwires fabricated by ultrarapid solidification techniques, new observations and opportunities are offered. They are fabricated in a continuous way with up to hundred-meter length and diameter in the range 0.1-90 μm for the so-called glass-coated microwires [10][11][12] and around 120-180 μm for the in-waterquenched ones. [13] Such ultrarapid solidification techniques introduce very strong mechanical stresses that determine most of the magnetic properties which have been reviewed in other studies. [14][15][16]