arXiv subjects

Huan Tan

Publications and source records attributed to Huan Tan.

4 recordsLinked to original sources

arXiv2026

Light-modulated exchange bias in multiferroic heterostructures

Magnetic straintronics, the strain-mediated control of magnetic anisotropy, has emerged as a key direction for next-generation energy-efficient technologies. In multiferroic heterostructures, magnetoelectric coupling is typically achieved by applying an electric field on a ferroelectric phase, inducing strain through the converse piezoelectric effect, which is then transferred to the adjacent ferromagnetic phase. As an alternative, strain can be remotely modulated through the photostrictive effect induced by light. While light-driven control of magnetic anisotropy has been explored, optical modulation of more complex phenomena such as exchange bias remains largely unaddressed. Here, we demonstrate significant light-induced modulation of exchange bias and magnetization switching at room temperature in a Pb(Mg1/3Nb2/3)O3-Pb(Zr,Ti)O3 (PMN-PZT)/Fe80Ga20(FeGa)/Ir20Mn80(IrMn) multiferroic heterostructure, driven by visible-light-photostriction. The magnetization state correlates with the light intensity, enabling multi-level states with light power densities as low as 0.1 W cm-2. These findings suggest a promising route toward low-power, multistate, and wireless opto-magnetic memory applications.

cond-mat.mtrl-sci↗

arXiv2025

Carbon magneto-ionics: Control of magnetism through voltage-driven carbon transport

Control of magnetism through voltage-driven ionic processes (i.e., magneto-ionics) holds potential for next-generation memories and computing. This stems from its non-volatility, flexibility in adjusting the magnitude and speed of magnetic modulation, and energy efficiency. Since magneto-ionics depends on factors like ionic radius and electronegativity, identifying alternative mobile ions is crucial to embrace new phenomena and applications. Here, the feasibility of C as a prospective magneto-ionic ion is investigated in a Fe-C system by electrolyte gating. In contrast to most magneto-ionic systems, Fe-C presents a dual-ion mechanism: Fe and C act as cation and anion, respectively, moving uniformly in opposite directions under an applied electric field. This leads to a 7-fold increase in saturation magnetization with magneto-ionic rates larger than 1 emu cm-3 s-1, and a 25-fold increase in coercivity. Since carbides exhibit minimal cytotoxicity, this introduces a biocompatible dimension to magneto-ionics, paving the way for the convergence of spintronics and biotechnology.

cond-mat.mtrl-sci↗

arXiv2025

Charge-transfer-mediated boron magneto-ionics: Towards voltage-driven multi-ion transport

Voltage control of magnetism via magneto-ionics, where ion transport and/or redox processes drive magnetic modulation, holds great promise for next-generation memories and computing. This stems from its non-volatility and ability to precisely tune both the magnitude and speed of magnetic properties in an energy-efficient manner. However, expanding magneto-ionics to incorporate novel mobile ions or even multiple ion species is crucial for unlocking new phenomena and enabling multifunctional capabilities. Here, we demonstrate voltage-driven multi-ion transport in a FeBO system with increasing oxygen content, progressively transitioning from an electrostatic-like response to a more pronounced electrochemical (magneto-ionic) behavior. The voltage-driven transport of both B and Fe is activated by oxidation state tuning, owing to the larger electronegativity of oxygen. Such charge-transfer effects allow multi-ion magneto-ionics, where O ions move oppositely to Fe and B ions. These results pave the way for programmable functionalities by leveraging elements with different electron affinities through charge-transfer engineering.

cond-mat.mtrl-sci↗

arXiv2021

Polarization and resistive switching in epitaxial 2 nm Hf$_{0.5}$Zr$_{0.5}$O$_2$ tunnel junctions

In the quest for reliable and power-efficient memristive devices, ferroelectric tunnel junctions are being investigated as potential candidates. CMOS-compatible ferroelectric hafnium oxides are at the forefront. However, in epitaxial tunnel devices with thicknesses around ${\approx}$ 4 - 6 nm, the relatively high tunnel energy barrier produces a large resistance that challenges their implementation. Here, we show that ferroelectric and electroresistive switching can be observed in ultrathin 2 nm epitaxial Hf$_{0.5}$Zr$_{0.5}$O$_2$ (HZO) tunnel junctions in large area capacitors (${\approx} 300μm^2$). We observe that the resistance area product is reduced to about 160 $Ω{\cdot}$cm$^2$ and 65 $Ω{\cdot}$cm$^2$ for OFF and ON resistance states, respectively. These values are two orders of magnitude smaller than those obtained in equivalent 5 nm HZO tunnel devices while preserving a similar OFF/ON resistance ratio (210 ${\%}$). The devices show memristive and spike-timing-dependent plasticity (STDP) behavior and good retention. Electroresistance and ferroelectric loops closely coincide, signaling ferroelectric switching as a driving mechanism for resistance change.

physics.app-ph↗