Ba2YIrO6: A cubic double perovskite material withIr5+ions

Abstract

Materials with a 5d 4 electronic configuration are generally considered to have a nonmagnetic ground state (J = 0). Interestingly, Sr2YIrO6 (Ir 5+ having 5d 4 electronic configuration) was recently reported to exhibit long-range magnetic order at low temperature and the distorted IrO6 octahedra were discussed to cause the magnetism in this material. Hence, a comparison of structurally distorted Sr2YIrO6 with cubic Ba2YIrO6 may shed light on the source of magnetism in such Ir 5+ materials with 5d 4 configuration. Besides, Ir 5+ materials having 5d 4 are also interesting in the context of recently predicted excitonic types of magnetism. Here we report a single-crystal-based analysis of the structural, magnetic, and thermodynamic properties of Ba2YIrO6. We observe that in Ba2YIrO6 for temperatures down to 0.4 K, long-range magnetic order is absent but at the same time correlated magnetic moments are present. We show that these moments are absent in fully relativistic ab initio band-structure calculations; hence, their origin is presently unclear.

Magnetism out of antisite disorder in the J=0 compound Ba2YIrO6

“…This is in line with the observation by Dey et al The amount of Y 2 O 3 increases to 6% in BYIO-4d-Q and 11% in BYIO-16d. Dey et al 9 proposed that the observed Y 2 O 3 exists as inclusions in crystals. While this is quite likely, we occasionally observe under optical microscope isolated Y 2 O 3 in BYIO-16d.…”

“…al. 9 suggested the magnetism in Ba 2 YIrO 6 was due to paramagnetic impurities. In a later study 11 , they identified a Schottky anomaly in the specific heat of Sr 2 YIrO 6 pointing to the conclusion that paramagnetic impurities are responsible for the observed Curie susceptibilities without the onset of long range magnetic order.…”

Spontaneous Spin Textures in Multiorbital Mott Systems

“…Several experimental realizations of excitonic magnetism have already been discussed in the literature. [19][20][21][22][23] Model. We use the dynamical mean-field theory (DMFT) to study the minimal model of an excitonic magnet -the two-orbital Hubbard Hamiltonian at half- filling…”

Possibility of an unconventional spin state ofIr4+inBa21Ir9O43Yang1, Jeong2, Arakcheeva3 et al. 2016Phys. Rev. B0000View full textAdd to dashboardCite

“…In tetravalent (Ir 4+ ) 5d 5 iridates, such as Sr 2 IrO 4 [8][9][10], a complex spin-orbit entangled J eff = 1/2 state is realized, with a reduced bandwidth due to the splitting from the J eff = 3/2 states, which leads to the localization of electrons even by a relatively small on-site Coulomb interaction compared to their 3d counterparts. Additional effects of SOC include XY anisotropy [11,12], locking of the magnetic moment to the correlated rotation of oxygen octahedra in Sr 2 IrO 4 [13], anisotropic dimer excitations in Sr 3 Ir 2 O 7 [14], and Kitaev-type magnetic interactions in Na 2 IrO 3 [15].…”

“…Recent focus has been on new iridate compounds where experimental discoveries have strongly challenged theoretical predictions. For example, in pentavalent (Ir 5+ ) 5d 4 iridates a strong SOC is predicted to realize a nonmagnetic J = 0 state [4], but substantial magnetic moments have been found in Ba 2 YIrO 6 [5] and especially in Sr 2 YIrO 6 [6], where structural distortion of the octahedral environment leads to 0.91 μ B /Ir. Furthermore, a possible realization of a spinorbital liquid with Ir 5+ has been discussed for 6H hexagonal Ba 3 ZnIr 2 O 9 powder [7].…”