Single-ion anisotropy, Dzyaloshinskii-Moriya interaction and negative magnetoresistance of the spin-1/2 pyrochlores R2V2O7

Abstract

The electronic and magnetic properties of spin-1/2 pyrochlores R2V2O7 were investigated on the basis of density-functional calculations. Contrary to the common belief, the spin-1/2 V4+ ions are found to have a substantial easy-axis single-ion anisotropy. The |D/J| ratio deduced from the magnon quantum Hall effect of Lu2V2O7, where J is the nearest-neighbor spin exchange and D is the Dzyaloshinskii-Moriya parameter, is much greater than the value estimated from our calculations (i.e., 0.32 vs. 0.05). We show that this discrepancy is due to the neglect of the single-ion anisotropy of the V4+ ions, and the negative magnetoresistance observed for R2V2O7 arises from a new mechanism.

References in corpus (5)

• Magnetic Pyrochlore Oxides
• Observation of the Magnon Hall Effect
• Theory of Thermal Hall Effect in Quantum Magnets
• Origin of the Structural and Magnetic Anomaly of the Layered Compound SrFeO2: A Density Functional Investigation
• Cooperative Effect of Electron Correlation and Spin-Orbit Coupling on the Electronic and Magnetic Properties of Ba2NaOsO6

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