Magnetoelectric Coupling at the Ni/Hf_0.5Zr_0.5O₂ Interface

Abstract

Composite multiferroics containing ferroelectric and ferromagnetic components often have much larger magnetoelectric coupling compared to their single-phase counterparts. Doped or alloyed HfO2-based ferroelectrics may serve as a promising component in composite multiferroic structures potentially feasible for technological applications. Recently, a strong charge-mediated magnetoelectric coupling at the Ni/HfO2 interface has been predicted using density functional theory calculations. Here, we report on the experimental evidence of such magnetoelectric coupling at the Ni/Hf0.5Zr0.5O2(HZO) interface. Using a combination of operando XAS/XMCD and HAXPES/MCDAD techniques, we probe element-selectively the local magnetic properties at the Ni/HZO interface in functional Au/Co/Ni/HZO/W capacitors and demonstrate clear evidence of the ferroelectric polarization effect on the magnetic response of a nanometer-thick Ni marker layer. The observed magnetoelectric effect and the electronic band lineup of the Ni/HZO interface are interpreted based on the results of our theoretical modeling. It elucidates the critical role of an ultrathin NiO interlayer, which controls the sign of the magnetoelectric effect as well as provides a realistic band offset at the Ni/HZO interface, in agreement with the experiment. Our results hold promise for the use of ferroelectric HfO2-based composite multiferroics for the design of multifunctional devices compatible with modern semiconductor technology.

Hafnium Oxide (HfO2) – A Multifunctional Oxide: A Review on the Prospect and Challenges of Hafnium Oxide in Resistive Switching and Ferroelectric Memories

“…Such multiferroic composites can be used in cheap magnetic sensors, magnetoelectric FET transistors, ultrahigh‐density nonvolatile magnetic memories [ 444 ] (e.g., MRAMs), and electric‐field controlled magnonic devices, but also in spintronic components like spin filters [ 445 ] and multiferroic tunnel junctions exhibiting both tunneling magnetoresistance and tunneling electroresistance effects. [ 446 ] The magnetoelectric coupling was recently demonstrated in Ni/HZO interface, [ 447–449 ] EuS/HZO bilayers, [ 450 ] Co/HfO 2 layers, [ 451 ] La 0.7 Sr 0.3 MnO 3 /HZO, [ 448 ] and CoFeB/HfO 2 [ 452 ] heterostructures, but will be probably present also in other multiferroic heterostructures consisting of ferroelectric HZO and ferromagnetic layers.…”

Composite Multiferroic Terahertz Emitter: Polarization Control via an Electric Field

“…One of the most important advantages of magnetoelectric multiferroics is the ability to reduce, by several orders of magnitude, energy consumption for the switching of magnetic states in spintronic and memory devices; this decreases to femto-and even attojoules [14][15][16][17][18]. Despite extensive and intensive development in the last decade of both the physics and technology of magnetoelectric multiferroics [19][20][21][22][23][24][25][26][27][28], a window of opportunity remains open for discovering effects that can further expand the field of application and improve the characteristics of devices based on these materials. Recently, an area of spintronics, terahertz (THz) spintronics, has been intensively developed.…”

Search for Magnetoelectric Coupling at the 57Fe/Hf0.5Zr0.5O2 Interface Using Operando Synchrotron Mössbauer Spectroscopy

“…The ferroelectric properties of the fabricated Pt/ 57 Fe/HZO/TiN capacitors were examined ex situ by using Cascade Summit 1100 probe station coupled with Agilent semiconductor device analyzer B1500A and in situ during SMS analysis with Agilent B2912A source‐measure unit. In both cases, pulsed switching and the positive‐up negative‐down (PUND) technique [ 46 ] were implemented (for details see Section S2, Supporting Information).…”

“…Using the combination of operando synchrotron based spectroscopic techniques, clear evidence of the ferroelectric polarization effect on the magnetic response of a nanometer‐thick Ni marker layer in functional Au/Co/Ni/HZO/W capacitors has been demonstrated. [ 46 ]…”