Researchers at NIST and JILA have developed a new technique using high-harmonic-generation (HHG) to probe the demagnetization dynamics of ferromagnetic alloys on femtosecond timescales. The technique, which employs a tabletop setup, allows scientists to observe the magnetic behavior of materials at nanometer spatial scales and femtosecond temporal scales.
The team, led by Tom Silva of the Electromagnetics Division’s Magnetics Group, has discovered that nickel and iron, two common elements in ferromagnetic alloys, respond differently to intense optical excitation. Iron reacts more rapidly than nickel, suggesting that optically-pumped angular momentum is transferred from iron to nickel during the demagnetization process.
The researchers plan to further refine their technique, aiming to achieve spatial resolution on the order of 1 nanometer in the near future. Their ultimate goal is to provide a comprehensive understanding of the quantum-mechanical and macroscopic phenomena involved in the demagnetization process, ultimately enabling the development of more advanced magnetic memory systems.
Source: https://www.nist.gov/news-events/news/2014/03/demagnetization-dynamics-femtosecond-time-scale
Keywords: Magnetic ordering, Femtosecond time scales, Nanometer spatial scales, Demagnetization process, Quantum-mechanical structure
