Tailoring of magnetic properties of ultrathin epitaxial Fe films by Dy doping

Abstract

We report on the controlled modification of relaxation parameters and magnetic moments of epitaxial Fe thin films through Dy doping. Ferromagnetic resonance measurements show that an increase of Dy doping from 0.1% to 5% gives a tripling in Gilbert damping, and more importantly a strongly enhanced anisotropic damping that can be qualitatively understood through the slow-relaxing impurity model. X-ray magnetic circular dichroism measurements show a pronounced suppression of the orbital moment of the Fe with Dy doping, leading to an almost threefold drop in the orbital to spin moment ratio, ml/ms. Doping with Dy can therefore be used to control both dynamic and static properties of thin ferromagnetic films for improved performance in spintronics device applications, mediated through the antiferromagnetic interaction of the 4f and 3d states.

Voltage Control of Rare-Earth Magnetic Moments at the Magnetic-Insulator–Metal Interface

“…The step field model can also be applied to nonmagnetic insulators and transition-metal ferromagnets (such as Fe, Co, and Ni, or their alloys) with RE ions at the interface that are antiferromagnetically coupled to the magnetic order [25,26] and facilitate a large coupling of the magnetization to electric fields. Good insulators, such as MgO, can endure very large electric fields (of the order of 300 mV=nm, in FeCojMgO, Ref.…”

Antidamping torques from simultaneous resonances in ferromagnet-topological insulator-ferromagnet heterostructures

“…Ultimately, this mechanism allows transfer of energy from the spin subsystem of the sample to the lattice. There are several mechanisms by which it may be enhanced, for example, through the introduction of rareearth impurities [35][36][37] , the presence of an adjacent rareearth layer 38 , or through spin pumping, wherein angular momentum is pumped out of an on-resonance ferromagnetic layer 39 .…”

Equilibrium current vortices in simple metals doped with rare earths

“…Examples are the spin-orbit torques [3], charge pumping [4], magnetoelastic interactions [5], and electric-field-induced magnetization dynamics [6,7]. The large intra-atomic SOI that governs the local moments of lanthanides with partially filled 4 f subshells causes novel spin charge coupling [8] and affects device parameters such as the magnetic damping [9,10]. Rareearth (RE) ions with local magnetic moments can partially or entirely substitute the nonmagnetic yttrium in the ferrimagnetic insulator yttrium iron garnet Y 3 Fe 5 O 12 (YIG) [11].…”