From Ultrafast Demagnetization to Ultrafast Spintronics : a 30 years story

Fuente: arXiv
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Autori principali: Remy, Quentin, Mangin, Stéphane
Natura: Preprint
Pubblicazione: 2026
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author Remy, Quentin
Mangin, Stéphane
author_facet Remy, Quentin
Mangin, Stéphane
contents The discovery of femtosecond laser-induced ultrafast demagnetization in 1996 opened a new field, femtomagnetism, in which magnetic order can be quenched on timescales shorter than a picosecond. This seminal observation revealed that angular momentum can be transferred out of the spin system with unprecedented speed, launching intense efforts to disentangle the roles of electrons, phonons, and spins in the non-equilibrium regime. Soon it became evident that ultrafast demagnetization generates spin-flips, spin polarization, magnons and spin currents, providing new channels for angular-momentum flow. These insights laid the foundation for linking femtomagnetism with spintronics. An emblematic breakthrough in this evolution is the helicity-independent single-pulse all-optical switching (AOS) observed in rare-earth transition-metal (RE-TM) ferrimagnets such as GdFeCo. This mechanism, operating at femtojoule-scale energies and without external magnetic fields, establishes RE-TM alloys as benchmark systems for understanding and exploiting angular-momentum flow at the femtosecond timescale. Building on these concepts, the combination of ultrafast optical excitation with spintronic devices has demonstrated deterministic magnetization reversal driven by femtosecond pulses in spin valves and tunnel junctions, including rare-earth-free systems. Ultrafast spin injection, acting analogously to spin transfer torque but operating three orders of magnitude faster, allows reversal of both ferromagnetic and ferrimagnetic layers. By enabling ultrafast and energy-efficient switching, ultrafast spintronics promises scalable technologies for high-speed information processing while raising fundamental questions about angular momentum transfer in strongly out-of-equilibrium quantum materials.
format Preprint
id arxiv_https___arxiv_org_abs_2604_25431
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle From Ultrafast Demagnetization to Ultrafast Spintronics : a 30 years story
Remy, Quentin
Mangin, Stéphane
Materials Science
The discovery of femtosecond laser-induced ultrafast demagnetization in 1996 opened a new field, femtomagnetism, in which magnetic order can be quenched on timescales shorter than a picosecond. This seminal observation revealed that angular momentum can be transferred out of the spin system with unprecedented speed, launching intense efforts to disentangle the roles of electrons, phonons, and spins in the non-equilibrium regime. Soon it became evident that ultrafast demagnetization generates spin-flips, spin polarization, magnons and spin currents, providing new channels for angular-momentum flow. These insights laid the foundation for linking femtomagnetism with spintronics. An emblematic breakthrough in this evolution is the helicity-independent single-pulse all-optical switching (AOS) observed in rare-earth transition-metal (RE-TM) ferrimagnets such as GdFeCo. This mechanism, operating at femtojoule-scale energies and without external magnetic fields, establishes RE-TM alloys as benchmark systems for understanding and exploiting angular-momentum flow at the femtosecond timescale. Building on these concepts, the combination of ultrafast optical excitation with spintronic devices has demonstrated deterministic magnetization reversal driven by femtosecond pulses in spin valves and tunnel junctions, including rare-earth-free systems. Ultrafast spin injection, acting analogously to spin transfer torque but operating three orders of magnitude faster, allows reversal of both ferromagnetic and ferrimagnetic layers. By enabling ultrafast and energy-efficient switching, ultrafast spintronics promises scalable technologies for high-speed information processing while raising fundamental questions about angular momentum transfer in strongly out-of-equilibrium quantum materials.
title From Ultrafast Demagnetization to Ultrafast Spintronics : a 30 years story
topic Materials Science
url https://arxiv.org/abs/2604.25431