Higgs and Goldstone spin-wave modes in striped magnetic texture

Matías Grassi (1) , Moritz Geilen (2) , Kosseila Ait Oukaci (3) , Yves Henry (1) , Daniel Lacour (3) , Daniel Stoeffler (1) , Michel Hehn (3) , Philipp Pirro (2) , Matthieu Bailleul (1)

1 IPCMS - Institut de Physique et Chimie des Matériaux de Strasbourg
2 TU Kaiserslautern - Technische Universität Kaiserslautern
3 IJL - Institut Jean Lamour

Spontaneous symmetry breaking is ubiquitous in physics. Its spectroscopic signature consists in the softening of a specific mode upon approaching the transition from the high symmetry side and its subsequent splitting into a zero-frequency "Goldstone" mode and a non-zero-frequency "Higgs" mode. Although they determine the whole system dynamics, these features are difficult to address in practice because of their vanishing coupling to most experimental probes and/or their strong interaction with other fluctuations. In this work, we consider a periodic magnetic modulation occurring in a ferromagnetic film with perpendicular-to-plane magnetic anisotropy and directly observe its Goldstone and Higgs spin-wave modes at room temperature using microwave and optical techniques. This simple system constitutes a particularly convenient platform for further exploring the dynamics of symmetry breaking.

Domaines: Autre [cond-mat.other]

Matías Grassi, Moritz Geilen, Kosseila Ait Oukaci, Yves Henry, Daniel Lacour, et al.. Higgs and Goldstone spin-wave modes in striped magnetic texture. Physical Review B, 2022, 105 (9), pp.094444. ⟨10.1103/PhysRevB.105.094444⟩. ⟨hal-03371103v2⟩