有望な固体冷却材料の冷却挙動を探る(Scientists probe chilling behavior of promising solid-state cooling material)

2024-07-01 オークリッジ国立研究所(ORNL)

＜関連情報＞

• https://www.ornl.gov/news/scientists-probe-chilling-behavior-promising-solid-state-cooling-material
• https://www.science.org/doi/10.1126/sciadv.adn2840

マグノンとフォノンのハイブリッド局在が強磁性ガラス状態近傍の機能を強化する Hybrid magnon-phonon localization enhances function near ferroic glassy states

MICHAEL E. MANLEY, PAUL J. STONAHA, NICKOLAUS M. BRUNO, IBRAHIM KARAMAN, […], AND JEFFREY W. LYNN
Science Advances  Published:14 Jun 2024
DOI:https://doi.org/10.1126/sciadv.adn2840

Abstract

Ferroic materials on the verge of forming ferroic glasses exhibit heightened functionality that is often attributed to competing long- and short-range correlations. However, the physics underlying these enhancements is not well understood. The Ni₄₅Co₅Mn_36.6In_13.4 Heusler alloy is on the edge of forming both spin and strain glasses and exhibits magnetic field–induced shape memory and large magnetocaloric effects, making it a candidate for multicaloric cooling applications. We show using neutron scattering that localized magnon-phonon hybrid modes, which are inherently spread across reciprocal space, act as a bridge between phonons and magnons and result in substantial magnetic field–induced shifts in the phonons, triple the caloric response, and alter phase stability. We attribute these modes to the localization of phonons and magnons by antiphase boundaries coupled to magnetic domains. Because the interplay between short- and long-range correlations is common near ferroic glassy states, our work provides general insights on how glassiness enhances function.