Current-driven periodic domain wall creation in ferromagnetic nano-wires

TL;DR

This paper predicts a universal, current-driven method for creating and injecting domain walls into ferromagnetic nano-wires without external magnetic fields, applicable to simple exchange ferromagnets.

Contribution

It introduces a novel, universal mechanism for periodic domain wall creation driven solely by electric current in simple ferromagnets, without requiring complex interactions.

Findings

Domain walls are injected periodically above a critical current

The period of injection scales as (j - j_c)^(-1/2)

The process is universal and independent of microscopic details

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 analytical and numerical results show that above a critical current $j_{c}$ domain walls are injected into the nano-wire with a period $T \sim (j-j_{c})^{-1/2}$. Importantly, domain walls can be produced periodically even in a simple exchange ferromagnet with uniaxial anisotropy, without requiring any standard "twisting" interaction like Dzyaloshinskii-Moriya or dipole-dipole interactions. We show analytically that this process and the period exponents are universal and do not depend on the peculiarities of the microscopic Hamiltonian. Finally we give a specific proposal for an experimental realization.