Direct Observation of Strong Anomalous Hall Effect and Proximity‐Induced Ferromagnetic State in SrIrO₃

Abstract

have gained a lot of interest. The iridates indeed display SOC which is on a similar energy scale than that of the electroncorrelation or the electronic bandwidth, [1] which favors new or exotic quantum electronic states. [2][3][4][5][6] However, in contrast to archetypical correlated 3d TMOs, the electron-electron correlation strength is often too small in the 5d TMOs to host ferromagnetism.For Sr 2 IrO 4 (n = 1), the SOC results in a spin-orbital mixed state of the Ir 4+ ion with a filled quadruplet pseudospin state J eff = 3/2 and a half-filled doublet J eff = 1/2. [7] Magnetic interaction of neighbored pseudospins leads to a basal (ab)-plane canted antiferromagnetic (AFM) Mottinsulator ground state with pseudospins locked to the oxygen octahedral rotation. [8][9][10] For n = 2, interlayer coupling weakens which leads to a spin-flop transition of the pseudospins with out-of-plane spin alignment along the c-axis and T N = 280 K. [11] In contrast, the perovskite phase SrIrO 3 (SIO) (n = ∞) displays paramagnetic semimetallic behavior due to an increased hybridization of Ir5d and O2p orbitals. [3,[12][13][14][15] Nevertheless, SIO is on the verge of a magnetic ground state and may display AFM or ferromagnetic (FM) properties as well, depending on the details of the Hubbard interaction U and the SOC. [12] Owing to a strong pseudospin-lattice coupling, [16] these can be finely tuned by structural modifications, especially with respect to the network of the corner-sharing IrO 6 octahedra which in turn enables a manipulation of the magnetism in SIO.The bulk structure of SIO consists in a distorted orthorhombic perovskite structure with in-phase and antiphase rotations of the IrO 6 octahedra (a − a − c + in Glazer notation). [17,18] However, a suppression of octahedral out-of-plane tilts, akin to the rotation pattern of Sr 2 IrO 4 can be achieved when ultrathin SIO films are epitaxially grown on cubic SrTiO 3 (STO) which concomitantly yields a metal-to-insulator transition (MIT). [19] Other type of structural distortions are likewise discussed as a possible source for magnetic properties of SIO. [20] For example, in SIO/STO superlattices the IrO 6 rotation pattern supports an AFM ground state, [21,22] where the ordering temperature T N can be controlled by the interlayer coupling, i.e., by the STO thickness [23] or epitaxial strain. [24] Meanwhile a lot of activities have been focused on SIO-based heterostructures including magnetic active layers, which seems The 5d iridium-based transition metal oxides have gained broad interest because of their strong spin-orbit coupling, which favors new or exotic quantum electronic states. On the other hand, they rarely exhibit more mainstream orders like ferromagnetism due to generally weak electron-electron correlation strength. Here, a proximity-induced ferromagnetic (FM) state with T C ≈ 100 K and strong magnetocrystalline anisotropy is shown in a SrIrO 3 (SIO) heterostructure via interfacial charge transfer by using a ferromagnetic insulator in contact with SIO. Electrical tra...

Controllable Itinerant Ferromagnetism in Weakly Correlated 5d SrIrO3

“…Enhancing correlations U by reducing dimensionality is a generic strategy to promote magnetic ordering. Typical examples include the Ruddlesden–Popper phase (Sr 2 IrO 4 and Sr 3 Ir 2 O 7 ) or spatial-confined perovskite counterparts; however, the ground state of these systems is an antiferromagnetic insulator. − Recently, ferromagnetic order was successfully introduced to metallic SIO by interfacing with magnetic-donor LaCoO 3 (LCO) utilizing a magnetic proximity effect. − To cultivate the magnetic SIO for spintronics applications, it is highly desired to explore further whether the proximity induced ferromagnetic phase can be controlled by charge or can exhibit a topological spin texture.…”

Intrinsic Ferromagnetism in 2D Fe2H with a High Curie Temperature

“…Cm Y 2 H has the same structure with Sc 2 H and therefore shows a similar property. Sc 2 H and Y 2 H have magnetic moments of 0.13 and 0.1 μ B on the TM atoms (Figure S22), respectively, comparable to 0.1 μ B in SrIO 3 69 and CeCu 2 Si 2 . 70…”

Ru‐Doping‐Induced Spin Frustration and Enhancement of the Room‐Temperature Anomalous Hall Effect in La2/3Sr1/3MnO3 Films

“…For instance, the significant AHE signals observed in the 3d/5d oxide heterostructures prove the existence of interfacial charge transfer and ferromagnetic proximity effect. [13][14][15] In the SrRuO 3, [16][17][18][19] SrCoO 3 , [20] and EuTiO 3 [21] films, the nonmonotonic magnetic field and temperature-dependent AHE not only signify the symmetry-protected nodal points in the band structure but also imply the spatial inhomogeneities in magnetism. On the other hand, AHE is an essential tool to read out the magnetic state in oxide-based spintronic devices.…”