---
title: "Micromagnetics: how magnetization finds its own texture"
description: "Eight chapters on how magnetization moves: precession and damping, switching, exchange, domain walls, spin waves and current-driven skyrmions, each with a Lab."
canonical_url: "https://sandboxphysics.com/stories/micromagnetics/"
language: "en"
page_type: "story"
alternate_languages:
  zh-CN: "https://sandboxphysics.com/zh/stories/micromagnetics/"
last_modified: "2026-10-30"
---

[Micromagnetics · A course with experiments](https://sandboxphysics.com/stories/micromagnetics/)

FROM ONE PRECESSING MOMENT TO A SKYRMION

# Micromagnetics: how magnetization finds its own texture

Nobody tells the magnetization where to point. Exchange, the stray field, anisotropy and damping decide it together. Start with one moment circling a field, build a domain wall and a spin wave from the same energy, then push a skyrmion along a track and check what its charge really says.

Sandbox Physics · 2026-10-29

One moment and its grid · Chapters 1–3

## What moves a magnetization

Watch one moment circle a field and settle, see how a magnet’s shape picks its easy axis, then let exchange smooth the magnetization and decide how fine the grid must be.

[Start with one moment →](https://sandboxphysics.com/stories/micromagnetics/precession-and-damping/)

Textures that move · Chapters 4–8

## Walls, waves and skyrmions

Push a domain wall past its Walker field, launch a spin wave, close a wall into a skyrmion, drive it with a current, then read a research paper’s charge figures yourself.

[Start with a domain wall →](https://sandboxphysics.com/stories/micromagnetics/domain-walls-and-walker-breakdown/)

## Eight chapters, with examples and experiments

1. [01 L1 A magnetic moment circles a field before it settles Why does a magnet in a field circle around it instead of turning straight to face it? Read and try →](https://sandboxphysics.com/stories/micromagnetics/precession-and-damping/)
2. [02 L2 A nanomagnet’s shape sets its easy axis and how it switches Why does a flat rectangle of magnetic film point along its long side, and how hard must you push to reverse it? Read and try →](https://sandboxphysics.com/stories/micromagnetics/shape-anisotropy-and-switching/)
3. [03 L2 Exchange smooths the magnetization and sets how fine the mesh must be How small must the cells of a micromagnetic simulation be, and how can you tell they are small enough? Read and try →](https://sandboxphysics.com/stories/micromagnetics/exchange-and-the-mesh/)
4. [04 L3 A field drives a domain wall only so fast Why does a domain wall speed up with the field only up to a threshold, and how does interfacial DMI move that threshold? Read and try →](https://sandboxphysics.com/stories/micromagnetics/domain-walls-and-walker-breakdown/)
5. [05 L3 How a small tilt travels through a magnet as a spin wave What wavelength does a spin wave of a given frequency have in a perpendicular film, and how far does it travel before damping stops it? Read and try →](https://sandboxphysics.com/stories/micromagnetics/spin-waves-and-dispersion/)
6. [06 L3 Why a skyrmion has a set size and a whole-number charge What sets the size of an isolated skyrmion in a film with interfacial DMI, what does its topological charge count, and why is the computed charge not exactly −1 next to an edge? Read and try →](https://sandboxphysics.com/stories/micromagnetics/skyrmions-and-topological-charge/)
7. [07 L4 A current pushes a skyrmion at an angle, and edges and weak spots decide where it ends up Why does a current move a skyrmion at an angle, and what do an edge and a weak spot do to that motion? Read and try →](https://sandboxphysics.com/stories/micromagnetics/current-driven-skyrmions/)
8. [08 L4 How to read a skyrmion charge and a pinning threshold in a simulation When a simulation reports a skyrmion charge that is not a whole number, or a current at which a skyrmion breaks free, how do you tell physics from numerical error? Read and try →](https://sandboxphysics.com/stories/micromagnetics/reading-skyrmion-charge-and-pinning-results/)

## Keep the experiments beside the chapters

The three Labs were built for this course and share its film parameters. Open one beside a chapter and set it to the numbers of the worked example.

[Kick a nanomagnet with a field pulse ↗](https://sandboxphysics.com/labs/macrospin-switching/) [Push a domain wall and launch spin waves ↗](https://sandboxphysics.com/labs/domain-wall-spin-waves/) [Drive a skyrmion along a track ↗](https://sandboxphysics.com/labs/skyrmion-track-pinning/)

Other magnetism Labs on the site

These Labs were built before this course, and their models do not use its solvers.

[Giant magnetoresistance in a spin valve ↗](https://sandboxphysics.com/labs/gmr-spin-valve/) [See domain walls as bright and dark lines in Lorentz TEM ↗](https://sandboxphysics.com/labs/lorentz-tem/) [Separate magnetic from electric phase in electron holography ↗](https://sandboxphysics.com/labs/electron-holography/)