{"id":416,"date":"2025-03-12T15:57:18","date_gmt":"2025-03-12T21:57:18","guid":{"rendered":"https:\/\/physlabs.colostate.edu\/chengroup\/?p=416"},"modified":"2025-03-13T18:04:05","modified_gmt":"2025-03-14T00:04:05","slug":"physicists-uncover-hall-mass-driving-spin-currents-sideways-in-advanced-magnets","status":"publish","type":"post","link":"https:\/\/physlabs.colostate.edu\/chengroup\/2025\/03\/12\/physicists-uncover-hall-mass-driving-spin-currents-sideways-in-advanced-magnets\/","title":{"rendered":"Physicists Uncover \u201cHall Mass\u201d Driving Spin Currents Sideways in Advanced Magnets"},"content":{"rendered":"\n

A team of researchers led by Colorado State University graduate student Luke Wernert and Associate Professor Hua Chen has discovered a new kind of \u201cHall effect\u201d that could enable more energy-efficient electronic devices. Their findings, published in Physical Review Letters<\/a> in collaboration with graduate student Basti\u00e1n Pradenas and Professor Oleg Tchernyshyov at Johns Hopkins University, reveal a previously unknown \u201cHall mass\u201d in complex magnets called noncollinear antiferromagnets.  <\/p>\n\n\n\n

The Hall effect\u2014first discovered by Edwin Hall at Johns Hopkins in 1879\u2014usually refers to electric current flowing sideways when exposed to an external magnetic field, creating a measurable voltage. This sideways flow underpins everything from vehicle speed sensors to phone motion detectors. But in the CSU team\u2019s work, electrons\u2019 spin (a tiny, intrinsic form of angular momentum) takes center stage instead of electric charge. Noncollinear antiferromagnets, unlike more familiar magnets where spins line up parallel or antiparallel, have spins oriented in different directions but still sum to zero net magnetization. This unique spin texture enables a fresh take on the Hall effect, where spin currents can flow at right angles rather than just electric charges. <\/p>\n\n\n\n

 \u201cImagine pushing a spin current in one direction and getting a second spin current going sideways,\u201d Wernert explains. \u201cThat\u2019s the hallmark of a Hall effect.\u201d The reason this new effect\u2014governed by the \u201cHall mass\u201d\u2014appears only in noncollinear antiferromagnets is because they have three degrees of freedom describing spin orientations. This extra complexity leads to three branches of spin waves (collective vibrations of the spins), two of which naturally flow sideways in response to a driving force. Experimentally, researchers can measure this Hall mass either by injecting spin waves from a conventional ferromagnet into a noncollinear antiferromagnet and detecting spin accumulation along the edges, or by using scattering techniques (like neutron or x-ray) to track the low-energy spin-wave spectrum. <\/p>\n\n\n

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\"A<\/figure>\n<\/div>\n\n\n

Because spin currents produce far less heat than electrical currents, harnessing them could revolutionize modern electronics. This prospect underlies the rapidly growing field of \u201cspintronics,\u201d which strives to build devices\u2014such as magnetic-based storage (Magnetoresistive Random-Access Memory, MRAM)\u2014that are more energy efficient and resistant to data corruption by external magnetic fields. In conventional magnetic materials, a stray magnetic field can sometimes wipe out stored information; by contrast, noncollinear antiferromagnets are much less susceptible to such interference, making them potentially safer for data storage and handling. Altogether, the discovery of this new Hall effect and its associated Hall mass opens an exciting direction in condensed matter physics and could guide the development of next-generation technology powered by spin. <\/p>\n\n\n\n

Luke Wernert, Basti\u00e1n Pradenas, Oleg Tchernyshyov, and Hua Chen, \u201cHall mass and transverse Noether spin currents in noncollinear antiferromagnets\u201d, arXiv:2404.12898<\/a>, Phys. Rev. Lett.<\/em> 134<\/strong>, 016706 (2025)<\/a>.<\/p>\n\n\n\n

Phys.org: A new kind of Hall effect: Physicists reveal potential of noncollinear antiferromagnets in spintronics<\/a><\/p>\n\n\n\n

CSU Source: Physics researchers discover new Hall Effect, making way for more energy-efficient technology<\/a><\/p>\n\n\n\n

<\/p>\n","protected":false},"excerpt":{"rendered":"

A team of researchers led by Colorado State University graduate student Luke Wernert and Associate Professor Hua Chen has discovered a new kind of \u201cHall effect\u201d that could enable more energy-efficient electronic devices. Their findings, published in Physical Review Letters in collaboration with graduate student Basti\u00e1n Pradenas and Professor Oleg Tchernyshyov at Johns Hopkins University, reveal a … <\/p>\n

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