Strain-induced magnetization control in an oxide multiferroic heterostructure

Abstract

Controlling magnetism by using electric fields is a goal of research towards novel spintronic devices and future nano-electronics. For this reason, multiferroic heterostructures attract much interest. Here we provide experimental evidence, and supporting DFT analysis, of a transition in La0.65Sr0.35MnO3 (LSMO) thin film to a stable ferromagnetic phase, that is induced by the structural and strain 2 properties of the ferroelectric BaTiO3 (BTO) substrate, which can be modified by applying external electric fields. X-ray Magnetic Circular Dichroism (XMCD) measurements on Mn L edges with a synchrotron radiation show, in fact two magnetic transitions as a function of temperature that correspond to structural changes of the BTO substrate. We also show that ferromagnetism, absent in the pristine condition at room temperature, can be established by electrically switching the BTO ferroelectric domains in the out-of-plane direction. The present results confirm that electrically induced strain can be exploited to control magnetism in multiferroic oxide heterostructures.

Interplay between morphology and magnetoelectric coupling in Fe/PMN-PT multiferroic heterostructures studied by microscopy techniques

“…Measuring an XMCD asymmetry image for two orthogonal sample orientations allows reconstructing a 2D vector map of the magnetization. A proper dedicated sample holder allows for application of a voltage up to 300 V across the sample thickness in situ [50]. Magnetization vector maps were measured after switching the polarization up or down, with zero applied electric field.…”

All-optical Helicity-Independent Switching State Diagram in Gd - Fe - Co Alloys

“…The conventional way to switch the magnetization is by applying a magnetic field, which normally requires high power consumption and complex circuit design [4,5]. Later, various methods for manipulating the magnetization without the magnetic field emerged continuously, including strain [6,7], electric field [8,9], heat [10,11], and polarized current [12,13]. However, the switching process in above cases usually happens via a coherent damping precession of the spins [14,15].…”

“…magnetic field emerged continuously, including strain 6,7 , electric field 8,9 , heat 10,11 and polarized current 12,13 . However, the switching process in above cases usually happens via a coherent damping precession of the spins 14,15 .…”

Reversible Modification of Ferromagnetism through Electrically Controlled Morphology

“…Specific sample holders were used, with silver paint used as bottom contact and a gold wire in contact with the Fe x Mn 1− x as top contact. The two contacts are then connected to a Keithley 6485 picoammeter/voltage source, which allows applying an out‐of‐plane electric voltage through the thickness of the sample up to ±300 V (6 kV cm −1 ), thus reversing the electrical polarization of the substrate without removing the sample from the measurement position.…”

“…The absence of multiferroics with the desired properties has pushed toward the investigation of heterostructures in which two components with different ferroic orders are coupled through an interface to obtain enhanced performances . The most typical example of this process is represented by ferromagnetic films deposited onto ferroelectric substrates . Three main mechanisms are reported in literature as responsible of the interfacial magnetoelectric coupling: charge accumulation or depletion at the interface, strain‐mediated effects and ion migration .…”