Anti-Magnet

A formula for building an ‘Antimagnet’ that can nullify the magnetic field has been developed by researchers at the Universitat Autònoma de Barcelona (UAB). The Spanish researchers have designed what they believe to be a new type of magnetic cloak, which shields objects from external magnetic fields, while at the same time preventing any magnetic internal fields from leaking outside, making the cloak undetectable. The development of such a device, described as an 'antimagnet', could offer many beneficial applications, such as protecting a ship's hull from mines designed to detonate when a magnetic field is detected, or allowing patients with pacemakers or cochlear implants to use other essential medical equipment.

For example, take the case of a patient with a pacemaker required to undergo an MRI scan. The MRI's large magnetic field interacts with the pacemaker and can cause serious damage to both the device and the patient. The metal in the pacemaker could also interact with and distort the MRI's large magnetic field, affecting the machine's detection capabilities.

The researchers are aware that the technology could also be used by criminals to dodge security systems, for example in airports and shops. Hence it is important for security officials to insist on designing safer detection systems and protocols.

A downside to using this material, however, is that it would distort an external magnetic field placed over the cloak, making it detectable, so the device would need to be combined with several outer layers of metamaterials, which have varying levels of magnetic field permeability, to correct this distortion and leave the magnetic field undisturbed.

The researchers aimed at three objectives:
*An object’s magnetic field will not penetrate the exterior once it is covered by the antimagnet.

*Everything cloaked by the antimagnet will be protected from external magnetic fields and the object inside will be undetectable.

*All materials used to create the antimagnet must be available, i.e. the antimagnet must be manufactured with the use of existing technology.

The antimagnet is designed to consist of several overlapping layers of materials with different magnetic properties, forming what is known as a metamaterial. The inner layer is made of a superconducting material that would function to stop a magnetic field from leaking outside of the cloak, which would be very useful to cover certain metals. It is then covered by several layers of ferromagnetic material, separated by air or other materials which do not have magnetic properties.

The researchers demonstrated the feasibility of the cloak using computer simulations of a ten-layered cylindrical device cloaking a single small magnet.