Events

Date: 19 November 2025   Time: 15:00 - 16:00

Location: GO Jones 610

The next CCMP seminar will be on Wednesday 19th at 15:00-16:00 in GO Jones 610. Dr Hariom Jani will be visiting us from the University of Oxford to discuss the topological properties of antiferromagnetic solitons.

Abstract:

Topological solitons are whirling structures in continuous fields that arise across various branches of physics, spanning from quantum to galactic length scales. Once created, these emergent textures are protected by topology, behaving as particle-like functional entities, particularly in condensed matter. A major goal in modern magnetism has been the creation and control of topological spin solitons, including skyrmions, merons and bimerons, as electrically controlled non-volatile elements for spintronic computing and communication devices. While substantial progress has been made in ferromagnets, such systems face intrinsic limitations: susceptibility to stray fields, large internal fields and slow, inefficient dynamics, hindering their performance. In this talk, I will introduce antiferromagnetic solitons as a promising solution to these challenges. These textures possess a rich ferroic order with a zero net magnetisation. As a result, they are robust, down-scalable, and predicted to exhibit efficient and ultrafast terahertz dynamics, making them 100-1000 times faster than conventional magnets.1 I will present how we first discovered these elusive textures by combining advances in quantum materials engineering and X-ray spectro-microscopy.2,3 By emulating the topological physics of the Kibble-Zurek mechanism,4 originally proposed in cosmology, we generated a broad family of nanoscale solitons at room temperature. These textures behave as emergent magnetic charges (including monopoles, dipoles, and quadrupoles), allowing direct readout of soliton vorticity.5 Importantly, antiferromagnetic solitons are tunable and can be engineered reproducibly using strain,6 temperature,2 fields4,7 and chirality.8 I will conclude by outlining prospective trends in leveraging antiferromagnetic materials as a platform for ultrafast soliton control, and how this could pave the way to energy-efficient spintronic and magnonic devices operating at terahertz frequencies.