2 research outputs found
Field-Free Switching of Perpendicular Magnetization in an Ultrathin Epitaxial Magnetic Insulator
For energy-efficient magnetic memories, switching of
perpendicular
magnetization by spināorbit torque (SOT) appears to be a promising
solution. This SOT switching requires the assistance of an in-plane
magnetic field to break the symmetry. Here, we demonstrate the field-free
SOT switching of a perpendicularly magnetized thulium iron garnet
(Tm3Fe5O12, TmIG). The polarity of
the switching loops, clockwise or counterclockwise, is determined
by the direction of the initial current pulses, in contrast with field-assisted
switching where the polarity is controlled by the direction of the
magnetic field. From Brillouin light scattering, we determined the
DzyaloshinskiiāMoriya interaction (DMI) induced by the PtāTmIG
interface. We will discuss the possible origins of field-free switching
and the roles of the interfacial DMI and cubic magnetic anisotropy
of TmIG. This discussion is substantiated by magnetotransport, Kerr
microscopy, and micromagnetic simulations. Our observation of field-free
electrical switching of a magnetic insulator is an important milestone
for low-power spintronic devices
Onset of Multiferroicity in Prototypical Single-Spin Cycloid BiFeO<sub>3</sub> Thin Films
In the room-temperature magnetoelectric multiferroic
BiFeO3, the noncollinear antiferromagnetic state is coupled
to the
ferroelectric order, opening applications for low-power electric-field-controlled
magnetic devices. While several strategies have been explored to simplify
the ferroelectric landscape, here we directly stabilize a single-domain
ferroelectric and spin cycloid state in epitaxial BiFeO3 (111) thin films grown on orthorhombic DyScO3 (011).
Comparing them with films grown on SrTiO3 (111), we identify
anisotropic in-plane strain as a powerful handle for tailoring the
single antiferromagnetic state. In this single-domain multiferroic
state, we establish the thickness limit of the coexisting electric
and magnetic orders and directly visualize the suppression of the
spin cycloid induced by the magnetoelectric interaction below the
ultrathin limit of 1.4 nm. This as-grown single-domain multiferroic
configuration in BiFeO3 thin films opens an avenue both
for fundamental investigations and for electrically controlled noncollinear
antiferromagnetic spintronics