Electromagnet Materials: Can They Stay Magnetized After Current is Switched Off?

In summary, the conversation discusses the concept of using a material inside a solenoid that can be quickly magnetized and then stay magnetized for a period of time after the current is switched off. This would allow for more energy to be derived from the system as the temporary magnet can be used to attract other materials and then easily demagnetized. However, there is a potential issue with the presence of magnetic materials resisting the current and potentially losing energy."
  • #1
jonnyk
81
0
Hi everyone,
Is there a material which, inside a solenoid, immediately or in a very short period of time gets magnetized as current is switched on and then stays magnetized for a while if the current is switched off? For if this were true then this would mean we could derive more energy out of the system as we put in. We magnetize the material, switch off the current then use that magnet to attract magntic material to it and derive energy from it. Then as the material is demagnetized after some time we can with much less energy remove the materials which were initally attracted to the temporary magnet. Then repeat the process. Wherein lies the problem?
 
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  • #2
jonnyk said:
… switch off the current then use that magnet to attract magntic material to it …

but wouldn't the presence of that magnetic material resist the current, so that it magnetised the magnet less in the first place, thereby losing energy?
 
  • #3
Permanent magnets are made by the process you describe. Every ferromagnetic substance will retain magnetic field due to hysteresis. Now you say we take an inductor put in magnetic energy, switch of the current. Now when you are putting in magnetic energy[1/2Li^2] this energy is not being given back to the battery rather it stays in the inductor and this is the enregy that is being used to attract magnetic materials.
 

FAQ: Electromagnet Materials: Can They Stay Magnetized After Current is Switched Off?

What are electromagnet materials?

Electromagnet materials are materials that have the ability to create a magnetic field when an electric current is passed through them. These materials typically consist of a ferromagnetic core, such as iron, surrounded by a coil of wire through which the current flows.

How do electromagnet materials stay magnetized?

Electromagnet materials stay magnetized due to the alignment of their atomic particles. When an electric current is passed through the material, the particles become aligned in the same direction, creating a strong magnetic field. This alignment can persist even after the current is switched off, as long as the particles remain in their aligned state.

Can electromagnet materials stay magnetized after the current is switched off?

Yes, in certain cases, electromagnet materials can stay magnetized after the current is switched off. This is known as residual magnetism. The strength and persistence of the magnetization depends on factors such as the strength of the current, the composition of the material, and the length of time the current was applied.

What factors can affect the magnetization of electromagnet materials?

The magnetization of electromagnet materials can be affected by several factors including the strength and duration of the current, the composition and shape of the material, and the presence of external magnetic fields. Additionally, high temperatures can cause electromagnet materials to lose their magnetization.

How are electromagnet materials used in everyday applications?

Electromagnet materials have a wide range of everyday applications, such as in motors, generators, speakers, and MRI machines. They are also used in electronic devices such as headphones, hard drives, and computer screens. Electromagnet materials are also commonly used in industrial settings for tasks such as lifting and separating metal objects.

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