Magnon gap excitations in van der Waals antiferromagnet MnPSe.

Magneto-spectroscopy methods have been employed to study the zero-wavevector magnon excitations in MnPSe. Experiments carried out as a function of temperature and the applied magnetic field show that two low-energy magnon branches of MnPSe in its antiferromagnetic phase are gapped. The observation of two low-energy magnon gaps (at 1.

Magneto-Optical Sensing of the Pressure Driven Magnetic Ground States in Bulk CrSBr.

Competition between exchange interactions and magnetocrystalline anisotropy may bring new magnetic states that are of great current interest. An applied hydrostatic pressure can further be used to tune their balance. In this work, we investigate the magnetization process of a biaxial antiferromagnet in an external magnetic field applied along the easy axis.

High-Angular Momentum Excitations in Collinear Antiferromagnet FePS.

We report on magneto-optical studies of the quasi-two-dimensional van der Waals antiferromagnet FePS. Our measurements reveal an excitation that closely resembles the antiferromagnetic resonance mode typical of easy-axis antiferromagnets; nevertheless, it displays an unusual, four-times larger Zeeman splitting in an applied magnetic field. We identify this excitation with an || = 4 multipolar magnon─a single-ion 4-magnon bound state─that corresponds to a full reversal of a single magnetic moment of the Fe ion.

High-Pressure Tuning of Magnon-Polarons in the Layered Antiferromagnet FePS.

Magnetic layered materials have emerged recently as promising systems to introduce magnetism in structures based on two-dimensional (2D) materials and to investigate exotic magnetic ground states in the 2D limit. In this work, we apply high hydrostatic pressures up to ≈ 8.7 GPa to the bulk layered antiferromagnet FePS to tune the collective lattice excitations (phonons) in resonance with magnetic excitations (magnons).

Spatially resolved optical spectroscopy in extreme environment of low temperature, high magnetic fields and high pressure.

We present an experimental setup developed to perform optical spectroscopy experiments (Raman scattering and photoluminescence measurements) with a micrometer spatial resolution in an extreme environment of low temperature, high magnetic field, and high pressure. This unique experimental setup, to the best of our knowledge, allows us to deeply explore the phase diagram of condensed matter systems by independently tuning these three thermodynamic parameters while monitoring the low-energy excitations (electronic, phononic, or magnetic excitations) to spatially map the Raman scattering response or to investigate objects with low dimensions. We apply this technique to bulk FePS, a layered antiferromagnet with a Néel temperature of T ≈ 120 K.