Anisotropic Magnetoresistance in Antiferromagnetic Sr2IrO4

We report point-contact measurements of anisotropic magnetoresistance (AMR) in a single crystal of antiferromagnetic Mott insulator Sr2IrO4 . The point-contact technique is used here as a local probe of magnetotransport properties on the nanoscale. The measurements at liquid nitrogen temperature rev...

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Bibliographic Details
Published in:Physical review. X 2014-11, Vol.4 (4)
Main Authors: Wang, C, Seinige, H, Cao, G, J.-S. Zhou, Goodenough, J B, Tsoi, M
Format: Article
Language:English
Subjects:
Antiferromagnetism
Crosstalk
Crystal structure
Crystallinity
Crystallography
Electric contacts
Electron transport
Ferromagnetism
Filing
Liquid nitrogen
Magnetic fields
Magnetic properties
Magnetism
Magnetoresistance
Magnetoresistivity
Materials science
Monitoring
Nanotechnology devices
Order parameters
Physics
Single crystals
Spin liquid
Spin-orbit interactions
Superconductivity
Symmetry
Transition metal alloys
Transport properties
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Summary:We report point-contact measurements of anisotropic magnetoresistance (AMR) in a single crystal of antiferromagnetic Mott insulator Sr2IrO4 . The point-contact technique is used here as a local probe of magnetotransport properties on the nanoscale. The measurements at liquid nitrogen temperature reveal negative magnetoresistances (up to 28%) for modest magnetic fields (250 mT) applied within the IrO2 a−b plane and electric currents flowing perpendicular to the plane. The angular dependence of magnetoresistance shows a crossover from fourfold to twofold symmetry in response to an increasing magnetic field with angular variations in resistance from 1% to 14%. We tentatively attribute the fourfold symmetry to the crystalline component of AMR and the field-induced transition to the effects of applied field on the canting of antiferromagnetic-coupled moments in Sr2IrO4 . The observed AMR is very large compared to the crystalline AMRs in 3d transition metal alloys or oxides (0.1%–0.5%) and can be associated with the large spin-orbit interactions in this 5d oxide while the transition provides evidence of correlations between electronic transport, magnetic order, and orbital states. The finding of this work opens an entirely new avenue to not only gain a new insight into physics associated with spin-orbit coupling but also to better harness the power of spintronics in a more technically favorable fashion.
ISSN:2160-3308
DOI:10.1103/PhysRevX.4.041034