Terahertz spectroscopy of antiferromagnetic resonances across a spin reorientation transition

Lee, Howon, Taek Sun Jung, Hyun Jun Shin, Sang Hyup Oh, Kyung Ik Sim, Taewoo Ha, Young Jai Choi, and Jae Hoon Kim. “Terahertz spectroscopy of antiferromagnetic resonances in YFe1− xMnxO3 0≤ x≤ 0.4 across a spin reorientation transition.” Applied Physics Letters 119, no. 19 (2021): 192903.

Abstract

We have conducted a terahertz spectroscopic study of antiferromagnetic resonances in bulk orthoferrite YFe_1−xMn_xO₃ (0≤x≤0.4). Both the quasi-ferromagnetic resonance mode and the quasi-antiferromagnetic resonance mode in the weak ferromagnetic Γ₄ phase disappear near the spin reorientation temperature, T_SR, for the onset of the collinear antiferromagnetic Γ₁ phase (x ≥ 0.1). Below T_SR, an antiferromagnetic resonance mode emerges and exhibits a large blueshift with decreasing temperature. However, below 50 K, this mode softens considerably, and this tendency becomes stronger with Mn doping. We provide a deeper understanding of such behaviors of the antiferromagnetic resonance modes in terms of the influence of the Mn³⁺ ions on the magnetocrystalline anisotropy. Our results show that terahertz time-domain spectroscopy is a useful, complementary tool in tracking magnetic transitions and probing the interaction between disparate magnetic subsystems in antiferromagnetic materials with multiple ionic species.

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