Measurement of the internal magnetic field in the correlated iridates Ca4IrO6, Ca

Abstract

Oxides containing iridium ions display a range of magnetic and conducting properties that depend on the delicate balance between interactions and are controlled, at least in part, by the details of the crystal architecture. We have used muon-spin rotation (µSR) to study the local field in four iridium oxides, Ca4IrO6, Ca5Ir3O12, Sr3Ir2O7 and Sr2IrO4, which show contrasting behavior. Our µSR data on Ca4IrO6 and Ca5Ir3O12 are consistent with conventional antiferromagnetism where quasistatic magnetic order develops below TN = 13.85(6) K and 7.84(7) K respectively. A lower internal field is observed for Ca5Ir3O12, as compared to Ca4IrO6 reflecting the presence of both Ir 4+and Ir 5+ ions, resulting in a more magnetically dilute structure. Muon precession is only observed over a restricted range of temperature in Sr3Ir2O7, while the Mott insulator Sr2IrO4 displays more complex behavior, with the µSR signal containing a single, well-resolved precession signal below TN = 230 K, which splits into two precession signals at low temperature following a reorientation of the spins in the ordered state.

Short review of high-pressure crystal growth and magnetic and electrical properties of solid-state osmium oxides

“…To date, significant evidence to reject the Slater model has not been discovered for NaOsO 3 . Similar phenomenology regarding the magnetic MIT has been observed for several 5d oxides such as Cd 2 Os 2 O 7 (T MIT = 226 K) [8,[76][77][78][79][80] and Ln 2 Ir 2 O 7 (T MIT = 36 K for Nd, 117 K for Sm, and 120 K for Eu) [50,[81][82][83][84][85][86] and studies of these oxides are in progress. As far as we know, NaOsO 3 is probably the best model material to investigate the nature of magnetic MIT and the Slater mechanism.…”

FromJeff=1/2insulator top-wave superconductor in single-crystalSrYuan1, Aswartham2, Terzic3 et al. 2015Phys. Rev. BSelf Cite384380View full textAdd to dashboardCite

“…4. There is a kink in M(T) for x=0 at 100 K that is attributed to a possible rearrangement of the magnetic order and is closely associated with magnetoresistivity [25], magnetoelectric effect [4] and unusual muon responses [26]. Ru doping suppresses the AFM transition T N from 240 K at x = 0 to zero at x = 0.49.…”

Model analysis of magnetic susceptibility of Sr2IrO4 : A two-dimensional Jeff=12

“…The result of fit points to the competing interlayer couplings between the nearest and next-nearest IrO 2 planes. The competing nature of interlayer couplings and the resultant complex stacking pattern of J eff = 1/2 isospin moments might give a clue for further unsettled issues of Sr 2 IrO 4 such as high-pressure suppression of weakferromagnetic moments [38] and the second magnetic transition below T N argued from the local probes [39].…”