Unconventional Magnetism in Spintronics: the emergence of Altermagnetism and its new variants

7th December 2023

Timing : 1 pm EST

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The discovery of d-wave magnetic order in momentum space has motivated a closer look at the symmetry classification of collinear magnetic systems. This has emerged as the third basic collinear magnetic ordered phase of altermagnetism, which goes beyond ferromagnets and antiferromagnets. Altermagnets exhibit an unconventional spin-polarized d/g/i-wave band structure in reciprocal space, originating from the local sublattice anisotropies in direct space. This gives properties unique to altermagnets (e.g., the spin-splitter effect), while also having ferromagnetic (e.g., polarized currents) and antiferromagnetic (e.g., THz spin dynamics and zero net magnetization) characteristics useful for spintronics device functionalities. A key consequence of d-wave magnetism is a new ability to manipulate its magnetic textures. We present a phenomenological theory of altermagnets, able to describe their unique magnetization dynamics and to model magnetic textures in this emergent collinear magnetic ordered phase. Focusing on the prototypical d-wave altermagnets, e.g. RuO2, we can explain intuitively the unique lifted degeneracy of their magnon spectra, and show that the altermagnetic domain walls, in contrast to antiferromagnets, have a finite gradient of the magnetization projection along the easy axis orientation, with its strength and direction connected to the altermagnetic anisotropy. This gradient generates a ponderomotive force in the domain wall in the presence of an external magnetic field, allowing the possibility to control the domains in a magnetically compensated ordered phase.



Snow
Dr. Jairo Sinova
Alexander von Humboldt Professor
Institute of Physics
Johannes Gutenberg University Mainz, Germany

Born in 1972, Sinova is an Alexander von Humboldt Professor of Physics at Johannes Gutenberg Universität Mainz. After completing his doctorate at Indiana University in 1999, he became a postdoc at the University of Tennessee and the University of Texas at Austin before becoming a professor of Physics at Texas A&M University in 2003. Among his honors, he has received the Alexander von Humboldt Professorship Award, the Johannes Gutenberg Research Fellowship, the ERC Advance Synergy Grant, National Science Foundation’s Career Award, the Cottrell Scholar Award, and was elected in 2011 a Fellow of the American Physical Society.