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Here\u2019s what you\u2019ll learn when you read this story:<\/p>\n
In 1845, Michael Faraday discovered what\u2019s known today as the Faraday Effect\u2014which describes how light and electromagnetism are related.<\/p>\n
A new study revealed that the magnetic component of light exerts a surprising influence on matter, affecting 17 percent of atomic spin in the visible spectrum and up to 75 percent in the infrared.<\/p>\n
This re-examination of the magnetic effect of light on matter could open up new possibilities for scientists to manipulate atomic spins, creating new forms of storage and sensor technologies.<\/p>\n
In the scientific history of the exploration of electricity and light, some pretty big names come to mind: Newton, Franklin, Maxwell, Edison<\/a>, and Tesla<\/a>, among others. However, in the world of electromagnetism, few names are quite as influential as Michael Faraday. Born to a poor family, Faraday became a self-taught scientist and eventually the prot\u00e9g\u00e9 of British chemist and inventor Humphrey Davy. His discoveries of electromagnetic induction (the basic principle behind all modern turbines) and the Faraday Effect (which describes how electromagnetism and light are related) eventually earned him a knighthood\u2014which he promptly turned down, wanting to remain \u201cplain Mr. Faraday to the end<\/a>.\u201d<\/p>\n Although electromagnetic induction is the foundation of industry, the Faraday Effect has an equally profound impact on physics. In 1845, Faraday designed an experiment with a light source, a system of polarizers, and electromagnets<\/a>. When light traveled through the two polarizers, quite expectedly, Faraday saw no light emitted at the other side. However, under the influence of the electromagnets, Faraday saw a \u201cminuscule but indistinguishable\u201d flicker of light, confirming that electromagnetism exhibits some influence on the electric field of light.<\/p>\n Fast forward 180 years, and scientists are still discovering new properties of this interplay between light<\/a> and magnetism. In a new study published in the journal Scientific Reports<\/a>, physicists Benjamin Assouline and Amir Capua from the Hebrew University of Jerusalem announce the finding that light can exhibit a magnetic influence in addition to an electric one. Specifically, this magnetic influence interacts with atomic spins\u2014a process once assumed to be too insignificant to be of any importance.<\/p>\n \u201cThe static magnetic field \u2018twists\u2019 the light, and the light, in turn, reveals the magnetic properties of the material<\/a>,\u201d Capua said in a press statement<\/a>. \u201cWhat we\u2019ve found is that the magnetic part of light has a first-order effect, it\u2019s surprisingly active in this process.\u201d<\/p>\n Using the Landau-Lifshitz-Gilbert (LLG) equation, which typically describes spin behavior in materials, Assouline and Capua demonstrated how light can create \u201cmagnetic torque\u201d that is actually similar to a static magnetic field. When applying this theoretical model to Terbium Gallium Garnet (TGG)\u2014a material commonly used to test the Faraday Effect\u2014the magnetic component of light accounted for 17 percent of atomic rotation in the visible spectrum. In the infrared<\/a> (with a wavelength up to 1,300 nanometers), that number jumped to a staggering 75 percent.<\/p>\n \u201cOur results show that light \u2018talks\u2019 to matter not only through its electric field, but also through its magnetic field<\/a>, a component that has been largely overlooked until now,\u2019 Assouline said.<\/p>\n According to Igor Rozhansky, a physicist at the University of Manchester who spoke with New Scientist<\/a>, a re-evaluation of the magnetic component of light could give scientists a new way to manipulate atomic spins, though it\u2019s uncertain how strong this effect will be in certain materials. Such fine-tuned manipulation, according to New Scientist, could lead to a new generation of spin-based sensors and hard drives<\/a>.<\/p>\n