# Point Curie (DD-669) > The Curie point, or Curie temperature, is named after Pierre Curie. His 1895 thesis, 'Propriétés magnétiques des corps à diverses températures' (Magnetic properties of substances at various temperatures), showed how magnetism changes with temperature. In a ferromagnet such as iron, a quantum effect called exchange interaction lines up the atoms' magnetic moments within small regions called domains. Above the Curie temperature, heat scrambles that alignment. The material loses its spontaneous magnetization and becomes paramagnetic: it's only weakly attracted to a magnet, and only while a field is applied. The Curie temperature is about 770 °C for iron, 358 °C for nickel and about 1,115 °C for cobalt. That's why a red-hot piece of iron stops sticking to a magnet and is attracted again as it cools. Being below the Curie point doesn't automatically make something a permanent magnet. In an ordinary iron nail the domains point in different directions and cancel out, which is why the nail isn't a magnet until it's magnetized. Antiferromagnets have a similar transition called the Néel temperature. The footage shows a torch heating a small metal piece until it glows, while a magnet on a rod hangs above it. - Department: Science (also Tech) - First published: 2025-11-05 - Last updated: 2025-11-05 - Permalink: https://detailenjoyer.com/case/point-curie/ - Author: Marcus Easterling (DetailEnjoyer), The Detail Department ## Quick facts - **DD-669-F01**: Iron's Curie temperature is about 770 °C. _(Write-up · Exhibit D (The numbers))_ - **DD-669-F02**: Pierre Curie published his findings in 1895. _(Write-up · Exhibit A (Named for Pierre Curie))_ ## Write-up Too hot to stick. Above its Curie point, iron stops being ferromagnetic. 1. **Named for Pierre Curie**: Pierre Curie's 1895 thesis showed how magnetism changes with temperature. 2. **Domains**: In a ferromagnet, atomic moments line up within small regions called domains. 3. **Heat scrambles them**: Above the Curie temperature, that alignment breaks down and the material becomes paramagnetic. 4. **The numbers**: The Curie temperature is about 770 °C for iron, 358 °C for nickel and about 1,115 °C for cobalt. 5. **Not every iron bar is a magnet**: Below the Curie point, domains can still cancel out, so an iron nail isn't a magnet until it's magnetized. ## Related case files - [Modern Mahjong (DD-017)](https://detailenjoyer.com/case/modern-mahjong/): Magnets at work - [Cloud Chambers (DD-623)](https://detailenjoyer.com/case/cloud-chambers/): Another physics demonstration - [Microwave Metal (DD-589)](https://detailenjoyer.com/case/microwave-metal/): I linked another case about metal and fields - [Shape Memory (DD-616)](https://detailenjoyer.com/case/shape-memory/): Another temperature-triggered change in a metal ## Reel vs. record - **Note**: 'Loses its permanent magnetism': more precisely, it loses its ferromagnetism, the ability to be strongly magnetized. Many iron objects below the Curie point aren't permanent magnets at all. - **Note**: 'Creating a stable magnetic field': alignment happens within domains. A piece of iron only makes a net field when its domains are mostly lined up, as in a magnetized bar. - **Missing numbers**: the Curie temperature is about 770 °C for iron, 358 °C for nickel and about 1,115 °C for cobalt. - **Note**: 'Becomes paramagnetic': correct. Above the Curie point the material is only weakly attracted to a magnet, which is why the glowing piece in the footage doesn't jump up. - **Missing**: it's named after Pierre Curie, whose 1895 thesis studied magnetism at different temperatures. The title's 'Point Curie' is my stylized title. ## Video: Point Curie: Too Hot to Stick - Duration: 19.0 s · Published: 2025-11-05 - File: https://detailenjoyer.com/assets/videos/DQr9-h_koa6.mp4 ### Transcript DID YOU KNOW? The Curie Point or Curie temperature is the critical temperature at which a ferromagnetic material such as iron, nickel, or cobalt loses its permanent magnetism and becomes paramagnetic. Below this temperature, the material's atomic magnetic moments align in the same direction due to strong internal interactions, creating a stable magnetic field. NOW YOU KNOW! ## Questions & answers **Q: Who is the Curie point named after?** A: His 1895 thesis. _(Source: Write-up · Exhibit A (Named for Pierre Curie) · Britannica: Curie point; Pierre Curie (1895): Propriétés magnétiques des corps à diverses températures (Internet Archive))_ **Q: About what is iron's Curie temperature?** A: Nickel's is about 358 °C. _(Source: Write-up · Exhibit D (The numbers) · Britannica: Curie point; Supermagnete: Curie temperature, explanations and illustrations)_ **Q: What does a ferromagnet become above its Curie point?** A: Only weakly attracted to magnets. _(Source: Write-up · Exhibit C (Heat scrambles them) · Britannica: Curie point; HyperPhysics (Georgia State University): Ferromagnetism)_ **Q: What are the regions of aligned atomic moments called?** A: Magnetic domains. _(Source: Write-up · Exhibit B (Domains) · Supermagnete: Curie temperature, explanations and illustrations; HyperPhysics (Georgia State University): Ferromagnetism)_ **Q: Why isn't every iron nail a magnet?** A: They cancel out until magnetized. _(Source: Write-up · Exhibit E (Not every iron bar is a magnet) · Supermagnete: Curie temperature, explanations and illustrations; HyperPhysics (Georgia State University): Ferromagnetism)_ ## Sources - [Britannica: Curie point](https://www.britannica.com/science/Curie-point) - [Pierre Curie (1895): Propriétés magnétiques des corps à diverses températures (Internet Archive)](https://archive.org/details/propritsmagntiq00curigoog) - [Supermagnete: Curie temperature, explanations and illustrations](https://www.supermagnete.de/eng/magnetism/Curie-temperature) - [HyperPhysics (Georgia State University): Ferromagnetism](http://hyperphysics.phy-astr.gsu.edu/hbase/Solids/ferro.html) ## Cite this case file Easterling, Marcus. "Point Curie." The Detail Department (DetailEnjoyer), case file DD-669, last updated Nov 5, 2025. https://detailenjoyer.com/case/point-curie/