Current-induced spin torque resonance of a magnetic insulator

Schreier, Michael; Chiba, Takahiro; Niedermayr, Arthur; Lotze, Johannes; Huebl, Hans; Geprägs, Stephan; Takahashi, Saburo; Bauer, G.; Gross, Rudolf; Goennenwein, Sebastian T. B.

doi:10.1103/physrevb.92.144411

Cited by 60 publications

(44 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As magnetic insulators, rare-earth iron garnets (R 3 Fe 5 O 12 ) or RIG constitute an important class of materials, which are promising for technological applications such as magnetic recording devices with giant magnetorestriction 1 , spin Seebeck insulators for thermoelectric generation 2 , microwave devices based on currentinduced spin torque resonance 3 , and Faraday rotators in optical telecommunications 4 . These systems are known to have two different types of Fe ions, namely experiencing a tetrahedral versus octahedral coordination environment ( Fig.…”

Section: Introductionmentioning

confidence: 99%

Properties of rare-earth iron garnets from first principles

Nakamoto

et al. 2017

Phys. Rev. B

View full text Add to dashboard Cite

Structural and magnetic properties of rare-earth iron garnets (RIG), which contain 160 atoms per unit cell, are systematically investigated for rare-earth elements varying from La to Lu (and including Y), by performing spin polarized density-functional calculations. The effects of 4f electrons (as core or as valence electrons) on the lattice constant, internal coordinates and bond lengths are found to be rather small, with these predicted structural properties agreeing rather well with available experiments. On the other hand, treating such electrons as valence electrons is essential to interpret the total magnetization measured in some RIG at low temperature, the different orientation and magnitude of the magnetizations that Fe and rare-earth ions can adopt and to also explain why some RIG have a compensation temperature while others do not. The magnetic exchange couplings and orbital-projected density of states are also reported for two representative materials, namely Gd3Fe5O12 and Nd3Fe5O12, when accounting for their 4f electrons.

show abstract

Section: Introductionmentioning

confidence: 99%

Properties of rare-earth iron garnets from first principles

Nakamoto

et al. 2017

Phys. Rev. B

View full text Add to dashboard Cite

show abstract

“…which shows a rectification effect as seen in microwave experiments [30] that spin currents are nonzero under pure ac bias, i.e.,…”

Section: Theorymentioning

confidence: 95%

Enhancing the spin transfer torque in magnetic tunnel junctions by ac modulation

et al. 2017

View full text Add to dashboard Cite

The phenomenon of spin transfer torque (STT) has attracted a great deal of interests due to its promising prospects in practical spintronic devices. In this paper, we report a theoretical investigation of STT in a noncollinear magnetic tunnel junction under ac modulation based on the nonequilibrium Green's function formalism, and derive a closed-formulation for predicting the time-averaged STT. Using this formulation, the ac STT of a carbon-nanotube-based magnetic tunnel junction is analyzed. Under ac modulation, the low-bias linear (quadratic) dependence of the in-plane (out-of-plane) torque on bias still holds, and the sin θ dependence on the noncollinear angle is maintained. By photon-assisted tunneling, the bias-induced components of the in-plane and out-of-plane torques can be enhanced significantly, about 12 and 75 times, respectively. Our analysis reveals the condition for achieving optimized STT enhancement and suggests that ac modulation is a very effective way for electrical manipulation of STT.

show abstract

“…uration and a near out-of-plane measurement was performed while G ↑↓ was assumed to be real [40]. If we allow δ to vary we find that for a value of δ = -52…”

Section: Analysis Without Correction For Possible Spin Seebeck Contrimentioning

confidence: 99%

Driving and detecting ferromagnetic resonance in insulators with the spin Hall effect

et al. 2015

View full text Add to dashboard Cite

We demonstrate the generation and detection of spin-torque ferromagnetic resonance in Pt/Y 3 Fe 5 O 12 (YIG) bilayers. A unique attribute of this system is that the spin Hall effect lies at the heart of both the generation and detection processes and no charge current is passing through the insulating magnetic layer. When the YIG undergoes resonance, a dc voltage is detected longitudinally along the Pt that can be described by two components. One is the mixing of the spin Hall magnetoresistance with the microwave current. The other results from spin pumping into the Pt being converted to a dc current through the inverse spin Hall effect. The voltage is measured with applied magnetic field directions that range from in-plane to nearly perpendicular. When compared with theory, we find that the real and imaginary parts of the spin mixing conductance have out-of-plane angular dependences.

show abstract

Current-induced spin torque resonance of a magnetic insulator

Cited by 60 publications

References 43 publications

Properties of rare-earth iron garnets from first principles

Properties of rare-earth iron garnets from first principles

Enhancing the spin transfer torque in magnetic tunnel junctions by ac modulation

Driving and detecting ferromagnetic resonance in insulators with the spin Hall effect

Contact Info

Product

Resources

About