Current driven domain wall creation in ferromagnetic nano-wires

TL;DR

This paper predicts a method to electrically generate and inject domain walls into ferromagnetic nano-wires without external magnetic fields, revealing a universal process above a critical current.

Contribution

It introduces a theory for current-driven domain wall creation that is independent of specific microscopic details and does not require additional magnetic interactions.

Findings

Domain walls can be injected above a critical current $j_c$

The injection period scales as $(j - j_c)^{-1/2}$

The process is universal and applicable to simple exchange ferromagnets

Abstract

We predict the electrical generation and injection of domain walls into a ferromagnetic nano-wire without the need of an assisting magnetic field. Our theory shows that above a critical current $j_{c}$ domain walls are injected into the nano-wire with a period $T\sim (j-j_{c})^{-1/2}$. In a uniaxial anisotropy geometry this process does not require Dzyaloshinskii-Moria or dipole-dipole interaction and can be done in a simple exchange ferromagnet. We also show that this process and the period exponents are universal and do not depend on the peculiarities of the microscopic Hamiltonian.