QM tells us that only one component of angular momentum is measurable which conventionally taken to be Lz= 1/2. The other two components have an uncertain magnitude and direction and this is usually depicted as a Cone around measurement axis.
In a system of two or more electrons, how does one electron see the spin of others? Does it feel the magnetic moment of another electron in only parallel to it or antiparallel to it with a value of 1/2? The confusion which I face comes from the ferromagnetic materials in which all the spins tend to align with each other. What is meant by this alignment? Since two components of any individual spin cannot be determined, I think there will always be some uncertainty. Or just the z components of all spins align?