Revealing Controllable Anisotropic Magnetoresistance in Spin–Orbit Coupled Antiferromagnet Sr<sub>2</sub>IrO<sub>4</sub>

Lu, Ching Liang; Gao, Bin; Wang, Haowen; Wang, Wei; Yuan, Songliu; Dong, Shuai; Liu, Junming

doi:10.1002/adfm.201706589

Cited by 38 publications

(29 citation statements)

References 32 publications

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“…Magnetic field-induced changes in the AMR symmetry are unusual. They have been reported for Sr 2 IrO 4 [40,41], where magnetoelastic effects have been suggested as the origin [40]. Here, the strain state of the film is dominated by in-plane compressive strain from the substrate, which can determine magnetic anisotropies [42], but is not expected to change as a function of the magnetic field.…”

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confidence: 74%

Anisotropic magnetoresistance in the itinerant antiferromagnetic EuTiO3

Ahadi

Salmani-Rezaie

et al. 2019

Phys. Rev. B

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We report on measurements of the anisotropic magnetoresistance (AMR) of doped EuTiO 3 . It is shown that the primary contribution to the AMR is the crystalline component, which depends on the relative orientation between the magnetic moments and the crystal axes. With increasing magnetic field, a four-fold crystalline AMR undergoes a change in its alignment with respect to the crystal axes. The results are discussed in the context the coupling between spin canting, electronic structure, and transport. We discuss the potential role of Weyl points in the band structure. At high fields, the AMR transitions to uniaxial symmetry, which is lower than that of the lattice, along with a cross-over from positive to negative magnetoresistance.3 Spin-orbit coupling plays a central role in the anisotropic magnetoresistance (AMR) and anomalous Hall effect (AHE) [1] of itinerant ferromagnets and in materials with topologically non-trivial electronic states. While an elegant theoretical framework exists for the intrinsic AHE and its connection to the Berry curvature of the electronic bands [2-7], AMR remains comparatively less well understood. Recently, both AMR and AHE have also attracted significant attention in antiferromagnetic metals and semiconductors [8,9]. For example, significant AHEs in non-collinear antiferromagnets have been discovered [10][11][12]. Another phenomenon of recent interest is the potential coupling between the orientation of the Néel vector and the topology of the electronic states in antiferromagnets with symmetry-protected Dirac and/or Weyl points in their band structure [13,14]. Both AHE and AMR can serve as signatures of such interactions [13][14][15].Degenerately doped, antiferromagnetic EuTiO 3 is an interesting testbed for these ideas for several reasons. Despite a small net magnetization, it exhibits an intrinsic AHE that changes sign as a function of the carrier density [16][17][18]. This is indicative of the Fermi level being located near a Weyl point or an avoided crossing, which are sources of Berry curvature [5,7]. Recent density functional calculations (DFT) show the presence of Weyl points, which are near the Fermi level for the doping concentration where the sign changes in the AHE are observed, in case of ferromagnetic order [17]. At zero applied fields, the Eu moments order antiferromagnetically (G-type) [19, 20] with a Néel temperature of ~6 K that is relatively insensitive to the amount of doping [17]. A collinear spin arrangement cannot give rise to Weyl points, because time reversal and inversion symmetry are both present. This can also be seen in DFT calculations (see Supplementary Information [21]). Under applied magnetic fields, however, the spins cant and produce a small net magnetization [17]. The Eu spin orientation can

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confidence: 74%

Anisotropic magnetoresistance in the itinerant antiferromagnetic EuTiO3

Ahadi

Salmani-Rezaie

et al. 2019

Phys. Rev. B

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“…Finally, we compare the measured AMR in SIO to , which is on the other side of the metal–insulator phase boundary. In , the canting of moments leads to an uncompensated moment within each of the planes, and these moments can be aligned by an external magnetic field, leading to a weakly ferromagnetic state [ 25 – 27 ]. The magnetic moments are coupled to the octahedral-site rotations by strong spin–orbit coupling, and the AMR can be explained by lattice distortions induced by magnetoelastic coupling.…”

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confidence: 99%

“…This brings the system closer to two-dimensional , in which the magnetic moments display canted in-plane antiferromagnetic order [ 23 , 24 ]. The magnetic state of was studied through anisotropic MR (AMR) measurements, which revealed a field-induced metamagnetic transition from an antiferromagnetic to a weakly ferromagnetic state [ 25 – 27 ]. Here, we use AMR measurements to study the correlation between electronic transport and magnetic order in ultrathin SIO.…”

Section: Introductionmentioning

confidence: 99%

Anisotropic magnetoresistance in spin–orbit semimetal $${\hbox {SrIrO}}_{3}$$

et al. 2020

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SrIrO 3 , the three-dimensional member of the Ruddlesden-Popper iridates, is a paramagnetic semimetal characterised by a the delicate interplay between spin-orbit coupling and Coulomb repulsion. In this work, we study the anisotropic magnetoresistance (AMR) of SrIrO 3 thin films, which is closely linked to spin-orbit coupling and probes correlations between electronic transport, magnetic order and orbital states. We show that the low-temperature negative magnetoresistance is anisotropic with respect to the magnetic field orientation, and its angular dependence reveals the appearance of a fourfold symmetric component above a critical magnetic field. We show that this AMR component is of magnetocrystalline origin, and attribute the observed transition to a field-induced magnetic state in SrIrO 3 .

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“…Combined with the structure utilizing the anisotropic magnetoresistance as shown in Fig. 1(a) [13,15,22], it can be translated into a corresponding probabilistic distribution in the electrical output signal − an essential component in the probabilistic computing or Bayesian learning. Finally, Fig.…”

Section: A Model Validationmentioning

confidence: 99%

Controllable Dispersion of Domain-Wall Movement in Antiferromagnetic Thin Films at Finite Temperatures

Semenov

2019

Phys. Rev. Applied

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The dynamics of a 90 • domain wall in an antiferromagnetic nanostrip driven by the currentinduced spin-orbital torque are theoretically examined in the presence of random thermal fluctuations. A soliton-type equation of motion is developed on the basis of energy balance between the driving forces and dissipative processes in terms of the domain wall velocity. Comparison with micromagnetic simulations in the deterministic conditions shows good agreement in both the transient and steady-state transport. When the effects of random thermal fluctuations are included via a stochastic treatment, the results clearly indicate that the dispersion in the domain wall position can be controlled electrically by tailoring the strength and duration of the driving current mediating the spin orbital torque in the antiferromagnet. More specifically, the standard deviation of the probability distribution function for the domain wall movement can be tuned widely while maintaining the average position unaffected. Potential applications of this unusual functionality include the probabilistic computing such as Bayesian learning.

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Revealing Controllable Anisotropic Magnetoresistance in Spin–Orbit Coupled Antiferromagnet Sr₂IrO₄

Cited by 38 publications

References 32 publications

Anisotropic magnetoresistance in the itinerant antiferromagnetic EuTiO3

Anisotropic magnetoresistance in the itinerant antiferromagnetic EuTiO3

Anisotropic magnetoresistance in spin–orbit semimetal $${\hbox {SrIrO}}_{3}$$

Controllable Dispersion of Domain-Wall Movement in Antiferromagnetic Thin Films at Finite Temperatures

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Revealing Controllable Anisotropic Magnetoresistance in Spin–Orbit Coupled Antiferromagnet Sr2IrO4

Cited by 38 publications

References 32 publications

Anisotropic magnetoresistance in the itinerant antiferromagnetic EuTiO3

Anisotropic magnetoresistance in the itinerant antiferromagnetic EuTiO3

Anisotropic magnetoresistance in spin–orbit semimetal $${\hbox {SrIrO}}_{3}$$

Controllable Dispersion of Domain-Wall Movement in Antiferromagnetic Thin Films at Finite Temperatures

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Revealing Controllable Anisotropic Magnetoresistance in Spin–Orbit Coupled Antiferromagnet Sr₂IrO₄