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Physicists at Carnegie Mellon University reported an in-plane anomalous Hall effect, announced on 19 August 2026 and published in Nature Materials.
It overturns the long-held assumption that a magnetisation-driven Hall response appears only when the magnetic field points perpendicular to the film.
The signal was produced in an atomically thin stack of the topological semimetal tantalum iridium telluride (TaIrTe4) on the ferromagnetic insulator chromium germanium telluride (Cr2Ge2Te6).
The low-symmetry stack preserves only a single mirror plane, letting the Hall response depend on both in-plane and out-of-plane magnetisation; it is also gate-tunable.
The Hall effect, found by Edwin H. Hall in 1879, already underlies two Nobel Prizes in Physics (1985 and 1998) and the modern electrical standards of the SI.
When a current-carrying conductor sits in a magnetic field, the Lorentz force pushes moving charges sideways. Charge piles up on one edge, producing a voltage perpendicular to both the current and the field. That transverse voltage is the Hall voltage.
Simple Analogy: A crosswind pushes marchers to one side of the road, crowding one kerb.
Edwin H. Hall, a graduate student at Johns Hopkins University, detects a transverse voltage across current-carrying gold foil in a magnetic field.
Hall reports the effect is roughly ten times stronger in ferromagnetic iron - the anomalous Hall effect.
Klaus von Klitzing discovers the quantum Hall effect while measuring Hall voltage in MOS field-effect transistors at low temperature and high magnetic field.
Daniel Tsui and Horst Stormer observe fractional steps in Hall conductance; Robert Laughlin explains them in 1983 as a quantum fluid of fractionally charged excitations.
Nobel Prize in Physics to Klaus von Klitzing for the quantised (integer) Hall effect.
Nobel Prize in Physics jointly to Robert B. Laughlin, Horst L. Stormer and Daniel C. Tsui for the fractional quantum Hall effect.
The revised SI takes effect; the quantum Hall effect and the von Klitzing constant underpin the realisation of the ohm and the ampere.
Carnegie Mellon University reports a magnetisation-driven in-plane anomalous Hall effect in a TaIrTe4/Cr2Ge2Te6 heterostructure, in Nature Materials.
Private research university whose Department of Physics, in the Mellon College of Science, produced and announced the in-plane anomalous Hall effect result published in Nature Materials.
The anomalous Hall voltage is a standard electrical read-out of a material's magnetisation, so a Hall response that also senses in-plane magnetisation could simplify how magnetic states are read in devices.
The result comes from stacking atomically thin layers; the property emerges from the interface and its lowered symmetry, not from either material on its own.
The quantum Hall effect gives a resistance quantised in exact fractions of the von Klitzing constant, which is why the ohm and the ampere in the revised SI rest on Hall physics.
TaIrTe4 is a topological semimetal; the finding gives physicists a fresh probe of multidimensional magnetic and topological configurations in condensed matter systems.
GS Paper 3 > Science & Technology - developments and their applications in everyday life; basic physics for Prelims
General Science > Physics - magnetism, current electricity and sensors
The appearance of a voltage across a current-carrying conductor, perpendicular to both the current and an applied magnetic field; discovered by Edwin H. Hall in 1879.
A Hall response arising from a material's own magnetisation rather than an external field; Hall found it in ferromagnetic iron in 1881.
A material whose electronic bands cross in ways protected by symmetry, giving unusual transport properties - TaIrTe4 is the one used in this device.