All-in-all-out magnetic domain size in pyrochlore iridate thin films as probed by local magnetotransport

Abstract

Pyrochlore iridates have attracted growing attention because of a theoretical prediction of a possible topological semimetal phase originating from all-in-all-out spin ordering. Related to the topological band structure, recent findings of the magnetic domain wall conduction have stimulated investigations of magnetic domain distribution in this system. Here, we investigate the size of magnetic domains in Eu 2 Ir 2 O 7 single crystalline thin films by magnetoresistance (MR) using microscale Hall bars. Two distinct magnetic domains of the all-in-all-out spin structure are known to exhibit linear MR but with opposite signs, which enables us to estimate the ratio of the two domains in the patterned channel. The linear MR for 80  60 m 2 channel is nearly zero after zero-field cooling, suggesting random distribution of domains smaller than the channel size. In contrast, the wide distribution of the value of the linear MR is detected in 2  2 m 2 channel, reflecting the detectable domain size depending on each cooling-cycle.Compared to simulation results, we estimate the average size of a single all-in-all-out magnetic domain as 1-2 m.

Topological Magnon Bands and Unconventional Superconductivity in Pyrochlore Iridate Thin Films

“…Alternatively, one can view our work as a study of spin (local moment) models with SOC on decorated kagome lattices, possibly artificially created in an optical lattice using artificial gauge fields to realize the SOC and spin interaction terms [58][59][60][61]. While experiments on Eu 2 Ir 2 O 7 provide evidence for an AIAO order in thicker thin films [62][63][64], theoretical studies on atomically thin bilayers and trilayers are less conclusive [41,52,53]. We find that, in the strong coupling limit and on the mean field level, the magnetic ground state is AIAO in the trilayer system, and closely related to it in the bilayer.…”

Spin ice Thin Film: Surface Ordering, Emergent Square ice, and Strain Effects

“…Classical spin ice [21] presents itself as a nascent paragon to lay the foundations of such concepts. This is further motivated by the recent growth of spin ice thin films of Dy 2 Ti 2 O 7 [22,23] and Ho 2 Ti 2 O 7 [24,25], along with the promising possibilities offered by spin ice heterostructures [26,27] and pyrochlore-iridates thin films [28][29][30][31][32][33][34].…”

“…The formulation of the local frustrated constraints in terms of effective gauge fields has revolutionized our perspective on these systems in both the classical and quantum domains. Depending on the system, this gauge symmetry can take the form of electromagnetism [2-5] with photon and magnetic-monopole excitations [5][6][7][8][9][10][11][12][13] [28][29][30][31][32][33][34].…”

Theory of Multifarious Quantum Phases and Large Anomalous Hall Effect in Pyrochlore Iridate Thin Films

“…Pyrochlore iridates, R 2 Ir 2 O 7 (R is a rare earth element or Y), are prominent examples of such systems and have been extensively studied in the last few years4567891011121314151617181920212223242526272829303132333435363738394041. Various novel phases have been proposed to occur as the results of the interplay between electron correlation and strong spin-orbit coupling, which include Weyl semimetal45, topological insulator56, Chern insulator67, chiral spin liquid8, axion insulator49, non-fermi-liquid10, and topological Mott insulator11.…”

“…Various novel phases have been proposed to occur as the results of the interplay between electron correlation and strong spin-orbit coupling, which include Weyl semimetal45, topological insulator56, Chern insulator67, chiral spin liquid8, axion insulator49, non-fermi-liquid10, and topological Mott insulator11. A great deal of experimental effort has been put forward to realize such phases in a number of pyrochlore iridate systems12131415161718192021222324252627282930313233.…”