I read a few of your posts, and you are very insightful on the topic of electromagnetism, i have a question for you.
I need a core for an Electro Magnet which will be able to be as strong as possible when it has a current applied, but will not be attracted to a permanent magnet when the current is turned off. (i.e. Steel can become a strong electro magnet, but will be attracted to a permanent magnet with or without a current, therefore I cannot use it.)
To make the experiment work as effectively as possible the core should be able to be converted to an electromagnet with minimal current, I thought about using Ferrite (Manganese Zinc) Round Bar? What will be the best gauge to use to get a strong magnet, but keep the current "voltage" as low as possible, even if is not as strong, i only require it to react with a neodymium magnet from a distance of at least 50mm - 100 mm. Do you have any suggestions on this topic?