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arXiv · 2512.22058

Spin Dynamics in the van der Waals Ferromagnet CrTe2 Engineered by Niobium Doping

Dhan Raj Lawati·Prem Bahadur Karki·Jitender Kumar·Karishma Prasad·Mohamed A. Elekhtiar·Kai Huang·Bibek Tiwari·Suvechhya Lamichhane·Rupak Timalsina·Zane Hubble·Ayodimeji E. Aregbesola·John Watt·Sy-Hwang Liou·Evgeny Y. Tsymbal·Jian Wang·Kapildeb Ambal·Abdelghani Laraoui
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Abstract

Understanding and controlling spin dynamics in two-dimensional (2D) van der Waals (vdW) ferromagnets is essential for their application in magnonics and hybrid quantum platforms. Here, we investigate the spin dynamics of the vdW ferromagnet 1T-CrTe_{2} and demonstrate their systematic tunability via niobium (Nb) substitution in Cr_{1-x}Nb_{x}Te_{2}(x=0-0.2). Ferromagnetic resonance (FMR) spectroscopy reveals that Nb doping enables wide-band tuning of the resonance frequency from 40 GHz down to the few-GHz regime, accompanied by a moderate increase in the Gilbert damping constant from ~0.066 to ~0.14, while preserving robust room-temperature ferromagnetism. Complementary magnetometry shows a concurrent reduction of the Curie temperature and saturation magnetization with increasing Nb content. Density functional theory calculations attribute the observed spin-dynamic trends to Nb-induced modifications of magnetic anisotropy and magnetic exchange interactions. Furthermore, CrTe_{2} flakes (~80 nm thick) exhibit lower resonance frequencies and damping than bulk crystals, consistent with thickness, surface/interface, and shape-dependent magnetic anisotropy. These results establish Nb-doped CrTe_{2} as a tunable vdW ferromagnet with controllable spin dynamics, extending its functionality from spintronics to broadband magnonics and quantum magnonics.

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Dhan Raj Lawati, Prem Bahadur Karki, Jitender Kumar, Karishma Prasad, Mohamed A. Elekhtiar, Kai Huang, Bibek Tiwari, Suvechhya Lamichhane, Rupak Timalsina, Zane Hubble, Ayodimeji E. Aregbesola, John Watt, Sy-Hwang Liou, Evgeny Y. Tsymbal, Jian Wang, Kapildeb Ambal, Abdelghani Laraoui. 2025-12-26. Spin Dynamics in the van der Waals Ferromagnet CrTe2 Engineered by Niobium Doping. https://doi.org/10.1002/adfm.77655

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