arXiv subjects

Soju Furuta

Publications and source records attributed to Soju Furuta.

3 recordsLinked to original sources

arXiv2025

Reply to "Comment on "Reconsidering the nonlinear emergent inductance: time-varying Joule heating and its impact on the AC electrical response"" by Yokouch et al

This is a response to the comments [arXiv:2407.15682 and Phys.Rev.B 111, 146401 (2025)] by Yokouchi et al. on our paper in Phys.Rev.B 110, 174402 (2024). In this Reply, we note that (i) their arguments lack a discussion of whether the overall characteristics of the observed nonlinear impedance, including its magnitude and unphysical negative inductance interpretation, can be explained by the emergent induction scenario, whereas the Joule heating model can, (ii) they incorrectly refer to the Joule heating model, and (iii) their new data in the Comment are also quantitatively explained by the Joule heating model. These findings suggest that, contrary to the opinion by Yokouchi et al., the overall behavior of the observed impedance is irrelevant to emergent induction.

cond-mat.mtrl-sci↗

arXiv2024

Reconsidering the nonlinear emergent inductance: time-varying Joule heating and its impact on the AC electrical response

A nonlinearly enhanced electrical reactance, $\Im Z$, under a large AC current has been measured to explore emergent inductors, which constitute a new class of inductors based on the spin-transfer torque effect. A nonlinear $\Im Z$ has been observed in conducting magnets that contain noncollinear spin textures and interpreted as the realization of an inductance due to current-induced spin dynamics. However, curious behavior has concomitantly been observed. For instance, the nonlinear $\Im Z$ always has a cutoff frequency of $10^0$--$10^4$ Hz, which is much lower than the resonance frequency of a ferromagnetic domain wall, $\sim$10$^7$ Hz; furthermore, the temperature and magnetic field variations in $\Im Z$ appear to be considerably correlated with those in the temperature derivative of resistance. This behavior appears to be difficult to understand in terms of the current-induced spin dynamics, and therefore, the earlier interpretation of the nonlinear $\Im Z$ should be further verified. Here, we theoretically and experimentally show that time-varying Joule heating and its impact on the AC electrical response can naturally explain these observations. In the experimental approach, we study the nonlinear AC electrical response of two conducting materials that exhibit no magnetic order, CuIr$_2$S$_4$ and 1$T$'-MoTe$_2$. Under time-varying Joule heating, a nonlinearly enhanced $\Im Z$ with the curious behavior mentioned above is observed in both systems. Our study implies that the nonlinear $\Im Z$ previously observed in noncollinear magnets includes a considerable contribution of the Joule-heating-induced apparent AC impedance.

cond-mat.mtrl-sci↗

arXiv2023

Symmetry of the emergent inductance tensor exhibited by magnetic textures

Metals hosting gradually varying spatial magnetic textures are attracting attention as a new class of inductor. Under the application of an alternating current, the spin-transfer-torque effect induces oscillating dynamics of the magnetic texture, which subsequently yields the spin-motive force as a back action, resulting in an inductive voltage response. In general, a second-order tensor representing a material's response can have an off-diagonal component. However, it is unclear what symmetries the emergent inductance tensor has and also which magnetic textures can exhibit a transverse inductance response. Here we reveal both analytically and numerically that the emergent inductance tensor should be a symmetric tensor in the so-called adiabatic limit. By considering this symmetric tensor in terms of symmetry operations that a magnetic texture has, we further characterize the magnetic textures in which the transverse inductance response can appear. This finding provides a basis for exploring the transverse response of emergent inductors, which has yet to be discovered.

cond-mat.mtrl-sci↗