|Title||Hall effect measurements on epitaxial SmNiO_3 thin films and implications for antiferromagnetism|
|Publication Type||Journal Article|
|Year of Publication||2013|
|Authors||Ha, SD, Jaramillo, R, Silevitch, DM, Schoofs, F, Kerman, K, Baniecki, JD, Ramanathan, S|
|Journal||Physical Review B|
|Keywords||Antiferromagnetism, Atomic Force Microscopy, Electronic Transport, Epitaxy, Magnetotransport, Metal-Insulator Transitions, Nickel Complex Oxides, Spin Density Waves, Sputtering, Thermopower, Thin Films, X-Ray Scattering|
The rare-earth nickelates (RNiO3) exhibit interesting phenomena such as unusual antiferromagnetic order at wave vector q = (½, 0, ½) and a tunable insulator-metal transition that are subjects of active research. Here we present temperature-dependent transport measurements of the resistivity, magnetoresistance, Seebeck coefficient, and Hall coefficient (RH) of epitaxial SmNiO3 thin films with varying oxygen stoichiometry. We find that from room temperature through the high temperature insulator-metal transition, the Hall coefficient is holelike and the Seebeck coefficient is electronlike. At low temperature the Néel transition induces a crossover in the sign of RH to electronlike, similar to the effects of spin density wave formation in metallic systems but here arising in an insulating phase ∼200 K below the insulator-metal transition. We propose that antiferromagnetism can be stabilized by band structure even in insulating phases of correlated oxides, such as RNiO3, that fall between the limits of strong and weak electron correlation.
|Short Title||Phys. Rev. B|