21. They are called ferroelectrics by analogy to ferromagnetic materials , which have spontaneous magnetization and exhibit similar hysteresis loops. 22. Ferromagnetic materials consist of magnetic domains.23. A typical GMR device consists of at least two layers of ferromagnetic materials separated by a spacer layer. 24. This is what happens when a piece of ferromagnetic material is " magnetized " and becomes a permanent magnet. 25. Ferromagnetic materials with high coercivity are called magnetically " hard " materials, and are used to make permanent magnets.26. The strength of this field can be greatly increased by placing a ferromagnetic material in the center of the coil. 27. With this first introduction of the metamaterial, it appears that the losses incurred were smaller than antiferromagnetic, or ferromagnetic materials . 28. Ferromagnetic materials can be divided into magnetically " soft " materials like microcrystalline structure, making them very hard to demagnetize.29. The simplest method of generating a spin-polarised current in a metal is to pass the current through a ferromagnetic material . 30. When the ferromagnetic material is magnetized, it biases the amorphous metal strip into saturation, where it no longer produces harmonics.
