Anisotropic Gigahertz Antiferromagnetic Resonances of the Easy-Axis van der Waals Antiferromagnet CrSBr.

Cham, Thow Min Jerald; Karimeddiny, Saba; Dismukes, Avalon H; Roy, Xavier; Ralph, Daniel C; Luo, Yunqiu Kelly · Nano Lett · 2022

basic_science · Level V

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Abstract

We report measurements of antiferromagnetic resonances in the van der Waals easy-axis antiferromagnet CrSBr. The interlayer exchange field and magnetocrystalline anisotropy fields are comparable to laboratory magnetic fields, allowing a rich variety of gigahertz-frequency dynamical modes to be accessed. By mapping the resonance frequencies as a function of the magnitude and angle of applied magnetic field, we identify the different regimes of antiferromagnetic dynamics. The spectra show good agreement with a Landau-Lifshitz model for two antiferromagnetically coupled sublattices, accounting for interlayer exchange and triaxial magnetic anisotropy. Fits allow us to quantify the parameters governing the magnetic dynamics: At 5 K, the interlayer exchange field is μ<sub>0</sub><i>H</i><sub><i>E</i></sub> = 0.395(2) T, and the hard and intermediate-axis anisotropy parameters are μ<sub>0</sub><i>H</i><sub><i>c</i></sub> = 1.30(2) T and μ<sub>0</sub><i>H</i><sub><i>a</i></sub> = 0.383(7) T. The existence of within-plane anisotropy makes it possible to control the degree of hybridization between the antiferromagnetic resonances using an in-plane magnetic field.