Rare-earth magnetism is dominated by localized 4f electrons, relative to inner transition metals (that are mostly comprised of lanthanides) and cannot be directly excited through an optical laser pulse. As a result, ultrafast demagnetization of rare-earth metals involves a distinct process in contrast to other elements of the periodic table. During demagnetization of rare-earth metals, researchers involve the excitation of magnons—a quasiparticle, viewed as a quantized spin wave. In a new report now published on Science Advances, B. Frietsch and a team of multidisciplinary scientists in physics, astronomy, mathematics and supercomputing in Germany, Sweden and the Czech Republic, disentangled the ultrafast dynamics of 5d6s and 4f valence band magnetic moments in terbium (Tb) metal using time-resolved photoemission spectroscopy. Based on the results of demagnetization, they established the coupling of 4f spins to the lattice structure through orbital momentum to provide an essential mechanism driving the dynamics of magnetization in technical materials with strong magnetic anisotropy.
from General Physics News - Science News, Physics News, Physics, Material Sciences, Science https://ift.tt/342e2bi
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