Wiktionary
a. (context physics English) unable to be magnetized; unaffected by a magnetic field
WordNet
adj. impervious to the effects of a magnetic field; resistant to magnetization; "an antimagnetic watch" [ant: magnetic]
Usage examples of "antimagnetic".
Sverdlov had simply installed a framework to support his refashioned accelerator rings, antimagnetic shielding circuits, and incidental wires, tubes, grids, capacitors, transformers.
A laser detect absent a magnetic detection would be a valid detonation signal, since the weapon would assume that either the magnetic sensor had failed, or that an antimagnetic anomaly device was in use.
The double-barreled handgun simultaneously fired a thermo-beam along with a stream of antimagnetic plastic bullets.
However there were disadvantages to such a 'hardened' field structure when under attack by high-impact antimagnetic missiles.