As i have said the primary magnetic field aligns surounding coils electrons so they form magnets that attract to each other (electron clustering)
We can see here how external fields affect electron spin.
When a piece of ferromagnetic material is placed into an external magnetic field, two things happen.
The spins in each domain shift so that the magnetic moments of the electrons become more aligned with the direction of the field.
Domains aligned with the field expand and take over regions previously occupied by domains aligned opposite to the field.
source
http://electron9.phys.utk.edu/phys136d/modules/m7/material.htmthis covers permanent magnets but still has relevant information
"Instead, every electron is a tiny magnet due to its inherent magnetism (what we call electron spin).
Furthermore, the alignment of the electron spins makes a hunk of iron (magnetite) into a magnetic lodestone.
All atoms have electrons with electron spin and magnetic fields due to their orbits about the nucleus. But not all material is magnetic like the lodestone (ferromagnetic). If the electron spins of an atom's electrons are aligned oppositely, their magnetic fields cancel. That's what happens with tissue paper, flesh, or other non-ferromagnetic substances.
Each iron atom, on the other hand, has four electrons whose spin magnetism doesn't cancel. They line up. Aligned magnetic fields make matter magnetic.
Iron is a peculiar, remarkable substance. Its aligned-field electrons spontaneously couple and form small long-lasting domains. The spins inside these microscopic domains are almost perfectly aligned. Most domains, though, aren't aligned. In common un-magnetized iron, many domains are randomly oriented"
source
http://www.usatoday.com/tech/columnist/aprilholladay/2005-04-01-wonderquest_x.htmSome materials are unsuitable like copper here it explains why
Since all matter is made up of atoms and all atoms have electrons that are in motion, do all atoms have magnetic fields?
The answer to this question is yes and no. All the electrons do produce a magnetic field as they spin and orbit the nucleus; however, in some atoms, two electrons spinning and orbiting in opposite directions pair up and the net magnetic moment of the atom is zero. Remember that the direction of spin and orbit of the electron determines the direction of the magnetic field. Electron pairing occurs commonly in the atoms of most materials. In the experiment you observed a helium atom showing two electrons spinning and orbiting around the protons and neutrons of the nucleus. The two electrons are paired, meaning that they spin and orbit in opposite directions. Since the magnetic fields produced by the motion of the electrons are in opposite directions, they add up to zero. The overall magnetic field strength of atoms with all paired electrons is zero.
source
http://www.ndt-ed.org/EducationResources/HighSchool/Magnetism/electronpairing.htm 
