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arXiv · 1802.09742

Magnetic field dependence of the nonlinear magnetic response and tricritical point in the monoaxial chiral helimagnet Cr$_{1/3}$NbS$_{2}$

Abstract

We present a comprehensive study of the magnetization dynamics and phase evolution in Cr$_{1/3}$NbS$_{2}$, which realizes a chiral soliton lattice (CSL). The magnetic field dependence of the ac magnetic response is analyzed for five harmonic components, $M_{nω}(H)$ $(n =1-5)$, using a phase sensitive measurement over a frequency range, $f = 11 - 10,000$ Hz. At a critical field, the modulated CSL continuously evolves from a helicity-rich to a ferromagnetic domain-rich structure, where the crossover is revealed by the onset of an anomalous nonlinear magnetic response that coincides with extremely slow dynamics. The behavior is indicative of the formation of a spatially coherent array of large ferromagnetic domains which relax on macroscopic time-scales. The frequency dependence of the ac magnetic loss displays an asymmetric distribution of relaxation times across the highly nonlinear CSL regime, which shift to shorter time-scales with increasing temperature. We experimentally resolve the tricritical point at $T_{TCP}$ in a temperature regime above the ferromagnetic Curie temperature which separates the linear and nonlinear regimes of the CSL at the phase transition. A comprehensive phase diagram is constructed which summarized the features of the field and temperature dependence of the magnetic crossovers and phase transitions in Cr$_{1/3}$NbS$_{2}$.

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BibTeXRIS

E. M. Clements, Raja Das, Manh-Huong Phan, Ling Li, Veerle Keppens, David Mandrus, Michael Osofsky, Hariharan Srikanth. 2018-12-31. Magnetic field dependence of the nonlinear magnetic response and tricritical point in the monoaxial chiral helimagnet Cr$_{1/3}$NbS$_{2}$. https://doi.org/10.1103/physrevb.97.214438

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