Zijing Zhang

We investigate the surface morphology and magnetic/electrical properties of NiFeCu thin films on ultra-smooth Xenomax (a type of polyimide) substrates with a particular focus on the bending dependence of the anisotropic magnetoresistance (AMR) effect. The surface roughness of the NiFeCu thin films on Xenomax substrates is as low as 0.26–0.45 nm, enabling the observation of a large AMR ratio of up to 0.86% without microfabrication. The magnetic easy axis of NiFeCu thin films rotates upon bending into convex or concave shapes depending on their magnetostriction constant, which is determined by the Ni composition. The behaviour of the AMR curves under bending is consistent with the magnetization curves obtained from the magneto-optical Kerr effect measurements. These bending characteristics can be attributed to the inverse magnetostrictive effect. Bending-induced magnetic tuning is a powerful tool for the development of high-performance flexible magnetic sensors.

Molecular electronics has received considerable attention because molecular devices can provide several unique properties, such as giant magnetoresistance,

We investigate the emergent magneto-inductance (EML) effect in NiFeCu thin films on ultra-smooth flexible polyimide substrates at room temperature, using an AC current and a stepwise external magnetic field. A large EML exceeding 3.4 μH is observed in Ni79Fe18Cu3, which has thin-film structures without specific spin textures in bulk materials. The observed EML is inversely proportional to the frequency and cross-sectional area, including film thickness and width. Our theoretical calculations reveal that this large EML originates from the spin motive force induced by the transient domain wall motion. Crucially, the enhancement is primarily attributed to a significant reduction in the domain wall pinning potential, in which the hard-axis magnetic anisotropy decreases.

Emergent inductance has attracted significant interest for its relevance in both interesting fundamental physics and practical applications in magnetic devices that demand miniaturization without compromising inductance. In this Letter, we report the discovery of a stepwise magnetic field-induced emergent magneto-inductance (EML) effect in Permalloy (Py) thin films deposited on polycarbonate (PC) substrates. Remarkably, Py/PC devices exhibit an exceptionally large inductance variation exceeding 1 μH at room temperature, and intriguingly, a sign reversal of inductance occurs around the zero magnetic field. The dependencies of the EML effect on frequency, step magnetic field changes, and film width can be explained from the theory based on the spin motive force driven by transient domain wall motion. This study opens up exciting avenues for advancing our understanding of emergent inductance in fundamental physics and paves the way for practical applications in flexible magnetic devices.