Which Material Can A Magnet Attract And Which Don't
How Magnetism Works
Understanding which materials respond and which don't is quite simple, but it depends on an understanding of how magnets work in general.  The motion of electrons in an atom produces a small magnetic field, but ordinarily, this field is cancelled out by the motion of other electrons and their opposing magnetic fields. However, in some materials, when you apply a magnetic field, the spins of neighboring electrons align with one another, which produces a net field across the whole material. In short, instead of cancelling each other’s fields, the electrons in these materials join together and make a stronger field. In some materials, this alignment disappears when the field is removed, but in others, it remains even after the field has been removed.
Metals That Attract Magnets
Ferromagnetic Metals and Alloys Ferromagnetic materials are attracted to magnets because their electrons spin and the resulting “magnetic moments” align easily, and retain that alignment even without an external magnetic field. Ferromagnetic materials such as iron, nickel and cobalt are therefore attracted to magnets, as well as rare-earth metals like gadolinium, neodymium and samarium. Alloys made from these materials are also attracted to magnets, Essentially, any alloy composed of ferromagnetic materials will also be magnetic.
Metals That Don't Attract Magnets
Paramagnetic Metals and Magnetism Paramagnetic metals have a weaker attraction to magnets than ferromagnetic metals, and they don’t retain their magnetic properties in the absence of a magnetic field. Paramagnetic metals include platinum, aluminum, tungsten, molybdenum, tantalum, cesium, lithium, magnesium, sodium and uranium. Diamagnetic Metals and Magnetism Diamagnetic metals are actually repelled by magnets rather than to enhance it. These materials include silver, lead, mercury and copper.