Selective Tuning of Gilbert Damping in Spin-Valve Trilayer by Insertion of Rare-Earth Nanolayers

Abstract

Selective tuning of the Gilbert damping constant, α, in a NiFe/Cu/FeCo spin-valve trilayer has been achieved by inserting different rare-earth nanolayers adjacent to the ferromagnetic layers. Frequency dependent analysis of the ferromagnetic resonances shows that the initially small magnitude of α in the NiFe and FeCo layers is improved by Tb and Gd insertions to various amounts. Using the element-specific technique of X-ray magnetic circular dichroism, we find that the observed increase in α can be attributed primarily to the orbital moment enhancement of Ni and Co, rather than that of Fe. The amplitude of the enhancement depends on the specific rare-earth element, as well as on the lattice and electronic band structure of the transition metals. Our results demonstrate an effective way for individual control of the magnetization dynamics in the different layers of the spin-valve sandwich structures, which will be important for practical applications in high-frequency spintronic devices.

XMCD and XMCD‐PEEM Studies on Magnetic‐Field‐Assisted Self‐Assembled 1D Nanochains of Spherical Ferrite Particles

“…XMCD Measurements : XA spectra at the Fe, Co, and Zn L 2,3 edges were acquired at room temperature on beamline I1011 at MAX‐Lab in Lund, Sweden . After normalization to the incident beam intensity, the XMCD was obtained as the difference between the two XA spectra measured with opposite circular polarizations .…”

Interlayer transmission of magnons in dynamic spin valve structures

“…Figure 4(a) shows the schematic structure of sample C. In this structure, we try to change the interfacial dissipation by capping RE layers on ferromagnetic layers. Here, we choose RE elements, Tb and Gd as insert layers because a similar structure has been studied in our previous study, 20 in which an antiferromagnetic coupling between the ferromagnetic and RE nanolayers was found and an antiferromagnetic interface can be induced. We speculate that such an antiferromagnetic interface may lead to an increasing of the interfacial dissipation.…”

“…Both hysteresis loops display a two-stepswitching behavior, suggesting a magnetic decoupling of the two TM layers by the Cu spacer, which is consistent with previous studies. 20 Two coercivity values H C,Py and H C,FeCo of the loops are obtained, corresponding to the Py and FeCo layers. Comparing the loops of samples A and C, we find that upon insertion of the Tb and Gd layers, the magnitudes of both H C,Py and H C,FeCo increase, from 5 Oe to 10 Oe for the Py layer and from 9 to 48 for FeCo layers, indicating the effect of RE insertions.…”

Applied Trends in Magnetic Rare Earth/Transition Metal Alloys and Multilayers

“…The dynamic properties of spin valves have rarely been studied, in spite of their relevance for high-frequency spintronic applications [ 55 ]. In particular, the use of spin valves in magnonic devices is of limited use given the lack of studies of their dynamics.…”