Tuning of magnetic and transport behavior in La0.67Sr0.33MnO3/Pr2Ir2O7 bilayer: Possible role of interfacial Dzyaloshinskii–Moriya interactions

Abstract

Here, we investigate the magnetic and electrical transport properties in epitaxial 3$d$-5$d$ based bilayer La_0.67Sr_0.33MnO${}_3$ (40 nm)/Pr${}_2$Ir${}_2$O${}_7$ (40 nm), grown on YSZ (001) substrate. While bulk La_0.67Sr_0.33MnO${}_3$ is ferromagnetic-metal and Pr${}_2$Ir${}_2$O${}_7$ is paramagnetic-metal but the later, due to heavy Ir, has significant spin–orbit coupling effect, which, in turn, will have large impact on electro-magnetic properties in adjacent ferromagnetic-layer through interfacial Dzyaloshinskii–Moriya interaction. Our temperature dependent magnetic measurements in bilayer reveal a prominent interlayer coupling below 42 K, which is further confirmed by exchange bias effect. The resistivity data indicates an insulating behavior, where the charge conduction mechanism follows Mott’s 2-dimensional variable-range-hopping model at high temperature. The bilayer shows negative magnetoresistance (MR) across the temperature but, in low temperature and low field, the MR exhibits distinct cusp which is characterized due to weak localization behavior. In contrast, the single-layer La_0.67Sr_0.33MnO${}_3$ (30 nm) deposited on SrTiO${}_3$ (100) substrate shows usual metallic behavior with a signature of Kondo-like resistivity minimum at low temperature. The single-layer shows power-law dependent negative MR, but no cusp unlike bilayer. This confirms an interface-driven exotic magnetic and transport properties in present bilayer which are quite intriguing and showcase its potential applications in spintronics and magnetic device technologies.