Magneto-transport properties in All-in-All-out magnetic ordered epitaxial Sm2Ir2O7 and Nd2Ir2O7 films
Abstract
Pyrochlore iridates R2Ir2O7 (R =rare earth element) have been predicted to exhibit a variety of exotic physical phenomena, such as the Weyl semimetallic state and topologically insulating behavior with all-in-all-out (AIAO) magnetic ordering. Here, we have observed a metal-insulator transition accompanied by the AIAO-type magnetic ordering in both Nd2Ir2O7 and Sm2Ir2O7 films below their respective ordering temperatures. Negative magnetoresistance (MR) is observed below 20 K and this gradually transitions into positive MR upon warming. We speculate that this characteristic negative MR is related to the f- d exchange coupling between the electrons at the Ir sites and localized moments at the R sites, which induces magnetic ordering on the R sub-lattice. Another remarkable feature is unconventional domain wall (DW) conductance. AIAO-type magnetic DW shows metallic behavior in Nd2Ir2O7 while Sm2Ir2O7 shows insulating behavior. This AIAO-type metallic (insulating) DW conductance is thought to be closely related to the existence of Weyl-semimetallic state (Mott insulating state) which is consistent with a recent theoretical prediction.
- Publication:
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APS March Meeting Abstracts
- Pub Date:
- March 2017
- Bibcode:
- 2017APS..MARV43001K