Novel room temperature Multiferroics for Random Access Memory Elements

TL;DR

This paper reports the fabrication of novel multiferroic materials that exhibit ferroelectricity and weak ferromagnetism at room temperature, enabling potential three-state memory devices with magnetic control.

Contribution

It introduces new PZT-PFW multiferroic materials fabricated via chemical solution deposition and pulsed laser deposition, demonstrating room-temperature multiferroicity with magnetic control of polarization.

Findings

Ferroelectricity and weak ferromagnetism above room temperature.

Magnetic field can switch polarization states.

Large polarization switching suitable for commercial devices.

Abstract

We have fabricated a variety of "PZT-PFW" (PbZr0.52Ti0.48O3)1-x(PbFe2/3W1/3O3)x [PZTFWx; 0.2 < x < 0.4] single-phase tetragonal ferroelectrics via chemical solution deposition (CSD) [polycrystalline] and pulsed laser deposition (PLD) [epitaxial] onto Pt/Ti/SiO2/Si(100) and SrTiO3/Si substrates. These exhibit ferroelectricity and (weak) ferromagnetism above room temperature with strain coupling via electrostriction and magnetostriction. Application of modest magnetic field strength ((mu)0H < 1.0 Tesla) destabilizes the long-range ferroelectric ordering and switches the polarization from ca. 22 (mu)C/cm2 (0.22 C/m2) to zero (relaxor state). This offers the possibility of three-state logic (+P, 0, -P) and magnetically switched polarizations. Because the switching is of large magnitude (unlike the very small nC/cm2 values in terbium manganites) and at room-temperature, commercial devices should be possible.