In addition to being highly reflective of zero-point photons, ferromagnetic materials can be induced with a permanent magnetic field. Their atoms can be such arranged that zero-point photons get polarized when inside the material. This is done by exposing a ferromagnetic material to a strong magnetic field.
From our knowledge of how Ampère’s right-hand rule works, we can see that such a field can be produced with electricity. If we wind a coil of copper wire around a piece of ferromagnetic material we get the required magnetic field by applying a direct current to the copper wire.
Highly polarized zero-point photons spin their way through the ferromagnetic material, pushing the atoms into place, thus inducing permanent magnetism into the material. Only ferromagnetic materials are receptive to this kind of treatment.