Topological Hall effect in weakly canted antiferromagnets

Nakane, Jotaro J.; Nakazawa, Kazuki; Kohno, Hiroshi

doi:10.1103/physrevb.101.174432

Cited by 21 publications

(10 citation statements)

References 23 publications

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“…To leading order in δθ and δφ, one finds 17,18) L 0 = 2 S dx 2a l • (n × ṅ), (10) up to a total time derivative. This shows that 2 S (l × n) is the canonical momentum conjugate to n. As a side note, the emergent gauge field, A AF,i = l • (∂ i n × n), demonstrated in 19) for canted antiferromagnets complies with this kinetic term.…”

Section: Lagrangian and Equations Of Motionmentioning

confidence: 64%

Magnetic-Field-Driven Antiferromagnetic Domain Wall Motion

Nakane,

Kohno

2021

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We theoretically study the antiferromagnetic domain wall motion actuated by an inhomogeneous external magnetic field. The Lagrangian and the equations of motion of antiferromagnetic spins under an inhomogeneous magnetic field are derived, first in terms of the Néel vector, and then using collective coordinates of the domain wall. A solution is found that describes the actuation of a domain wall by an inhomogeneous field, in which the motion is initiated by a paramagnetic response of wall magnetization, which is then driven by a Stern-Gerlach like force. The effects of pinning potential are also investigated. These results are in good agreement with atomistic simulations. While the present formulation contains the so-called intrinsic magnetization associated with Néel texture, a supplementary discussion is given to reformulate the theory in terms of physical magnetization without the intrinsic magnetization.

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Section: Lagrangian and Equations Of Motionmentioning

confidence: 64%

Magnetic-Field-Driven Antiferromagnetic Domain Wall Motion

Nakane,

Kohno

2021

Preprint

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“…This describes diffusion, dephasing, and relaxation of transverse spin density, generalizing the result of Ref. [25] to include magnetic impurities. Here,…”

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confidence: 79%

“…are, respectively, the spin-dephasing rate [24,25] and the (transverse) spin-relaxation rate. In Eq.…”

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confidence: 99%

Microscopic Calculation of Spin Torques in Textured Antiferromagnets

Nakane,

Kohno

2021

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A microscopic calculation is presented for the spin-transfer torques (STT) and damping torques in metallic antiferromagnets (AF). It is found that the sign of the STT is opposite to that in ferromagnets because of the AF transport character, and the current-to-STT conversion factor is enhanced near the AF gap edge. The dissipative torque parameter βn and the damping parameter αn for the Néel vector arise from spin relaxation of electrons. Physical consequences are demonstrated for the AF domain wall motion using collective coordinates, and some similarities to the ferromagnetic case are pointed out such as intrinsic pinning and the specialty of αn = βn. A recent experiment on a ferrimagnetic GdFeCo near its angular-momentum compensation temperature is discussed.

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“…Since A i j and l are considered small, we treat H perturbatively. 29) The unperturbed part H 0 describes electrons under a uniform AF moment, whose dispersion is…”

Section: The Equations Of Motion Can Then Be Written Explicitly Asmentioning

confidence: 99%

“…19 to interpret the experimental result of domain wall motion in a compensated ferrimagnet GdFeCo, 21) which is expected to be in the AF transport regime. 33) The STT v arising from the staggered spin density σn is calculated by considering the perturbation by the canting moment l. 29) Unlike the terms with β n and α n in Eq. ( 12) that arise in the presence of spin relaxation, the v -term does not require spin relaxation because it is a reactive STT.…”

Section: The Equations Of Motion Can Then Be Written Explicitly Asmentioning

confidence: 99%

Current-Induced Spin-Wave Doppler Shift in Antiferromagnets

Nakane,

Kohno

2021

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We theoretically study the spin dynamics in antiferromagnets (AFs) under the influence of an electric current. We identify two different sources of spin-transfer torques that stem from uniform (v n ) and staggered (v ) electron spin densities. While the former is well recognized, the latter is often overlooked. We show that both v n and v contribute equally to the spin-wave Doppler shift. Microscopic calculations are presented for electrons on a two-dimensional square lattice with nearest-neighbor (t) and next-nearest-neighbor (t ) hopping, which interpolate two opposite transport regimes of strongly-coupled AF (t /t 1) and two weakly-coupled ferromagnets (t /t 1). In the AF transport regime (t /t 1), v n and v have opposite signs, and the sign of the Doppler shift depends on band filling; v n (v ) is dominant near the AF gap (near the band bottom or the top). As t /t is increased, v n undergoes a sign change whereas v does not. In the limit of vanishing t, v n and v coincide and the spin-transfer torque reduces to that of ferromagnets.

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Topological Hall effect in weakly canted antiferromagnets

Cited by 21 publications

References 23 publications

Magnetic-Field-Driven Antiferromagnetic Domain Wall Motion

Magnetic-Field-Driven Antiferromagnetic Domain Wall Motion

Microscopic Calculation of Spin Torques in Textured Antiferromagnets

Current-Induced Spin-Wave Doppler Shift in Antiferromagnets

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