The core became a magnet

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atferrari

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To experiment in repelling a magnet I winded a 3-layers inductor around a piece of a common nail (soft-iron?)

Initially it seemed to work OK but later I found that, after cutting the current, the magnet was atracted by the core which started to behave as a magnet. Not what I wanted, precisely.

Just to be sure I verified that a paper clip is attracted by the core.

I did not foreseen that. How to avoid it? Not using a core? Or is this the wrong material?

Now that I think of it this would be good if I wanted to attract the magnet. But I want just the opposite.
 
Hola Colin,

If so, what could be a good material (that I could find easily around) serving as a core and not being converted into a magnet?

I am afraid that there is no any and I will have to build a really big solenoid.
 
atferrari said:
To experiment in repelling a magnet I winded a 3-layers inductor around a piece of a common nail (soft-iron?)
Click to expand...

It's not 'soft' - to use a nail in this way (a common school experiment) you need to 'soften' it - simply heat it until red hot, then let it slowly cool down, this will 'soften' it.

I did this with my daughter when she was at primary school
 
Hola Nigel.

After softening them like that, should I still expect some residual magnetism after use?

Not able to try it right now.
 
Hi,

To reduce the stored field of a material you do what is normally referred to as degaussing. This involves using an AC generated field that slowly decreases to excite the object to be demagnetized. As the AC field takes the object through its hysteresis loop and slowly decreases it takes the objects field with it and it becomes demagnetized.
 
He has asked for a material that will not have or produce any residual magnetism. A nail is steel and has a completely different magnetic dipole structure than Stalloy or other magnetic material used for DC electromagnets. Annealing a nail does not make it "soft iron." It simply anneals it.
 

And prevents it becoming a permanent magnet, which is the point behind doing it.

You also rather ignored my question?, can a ferrite rod be used as a core for an electro-magnet?.
 
You also rather ignored my question?, can a ferrite rod be used as a core for an electro-magnet?.
Click to expand...

I already said a ferrite rod can be used as the core of a DC electromagnet. Simply get an inductor and connect it to a battery. It will pick up LEDs and resistors and anything that has steel wires.
 
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