Giant facet-dependent spin-orbit torque and spin Hall conductivity in the triangular antiferromagnet IrMn3

A giant facet-dependent spin Hall conductivity is found in IrMn3 due to its chiral triangular antiferromagnetic structure. There has been considerable interest in spin-orbit torques for the purpose of manipulating the magnetization of ferromagnetic elements for spintronic technologies. Spin-orbit torques are derived from spin currents created from charge currents in materials with significant spin-orbit coupling that propagate into an adjacent ferromagnetic material. A key challenge is to identify materials that exhibit large spin Hall angles, that is, efficient charge-to-spin current conversion. Using spin torque ferromagnetic resonance, we report the observation of a giant spin Hall angle θSHeff of up to ~0.35 in (001)-oriented single-crystalline antiferromagnetic IrMn3 thin films, coupled to ferromagnetic permalloy layers, and a θSHeff that is about three times smaller in (111)-oriented films. For (001)-oriented samples, we show that the magnitude of θSHeff can be significantly changed by manipulating the populations of various antiferromagnetic domains through perpendicular field annealing. We identify two distinct mechanisms that contribute to θSHeff: the first mechanism, which is facet-independent, arises from conventional bulk spin-dependent scattering within the IrMn3 layer, and the second intrinsic mechanism is derived from the unconventional antiferromagnetic structure of IrMn3. Using ab initio calculations, we show that the triangular magnetic structure of IrMn3 gives rise to a substantial intrinsic spin Hall conductivity that is much larger for the (001) than for the (111) orientation, consistent with our experimental findings.

[1]  角田 匡清.  Thickness dependence of exchange anisotropy of polycrystalline Mn3Ir/Co-Fe bilayers , 2005 .

[2]  W. H. Kleiner.  SPACE-TIME SYMMETRY OF TRANSPORT COEFFICIENTS , 1966 .

[3]  D. Ralph,et al.  Spin-torque ferromagnetic resonance induced by the spin Hall effect. , 2010, Physical review letters.

[4]  S. Nakatsuji,et al.  Giant Anomalous Hall Effect in the Chiral Antiferromagnet Mn 3 Ge , 2015, 1511.04619.

[5]  C. Felser,et al.  Non-collinear antiferromagnets and the anomalous Hall effect , 2014, 1410.5985.

[6]  J. Slonczewski.  Current-driven excitation of magnetic multilayers , 1996 .

[7]  D. Ralph,et al.  Spin transfer torque devices utilizing the giant spin Hall effect of tungsten , 2012, 1208.1711.

[8]  T. Jungwirth,et al.  Spin Hall effect devices. , 2012, Nature materials.

[9]  Hafner,et al.  Ab initio molecular dynamics for open-shell transition metals. , 1993, Physical review. B, Condensed matter.

[10]  S. Parkin,et al.  Field cooling induced changes in the antiferromagnetic structure of NiO films. , 2001, Physical review letters.

[11]  M. Takahashi,et al.  Thickness dependence of exchange anisotropy of polycrystalline Mn3Ir/Co-Fe bilayers , 2005 .

[12]  J. S. Lee,et al.  Spin-transfer torque generated by a topological insulator , 2014, Nature.

[13]  A. Fert,et al.  Giant spin Hall effect induced by skew scattering from bismuth impurities inside thin film CuBi alloys. , 2012, Physical review letters.

[14]  E. Albisetti,et al.  Storing magnetic information in IrMn/MgO/Ta tunnel junctions via field-cooling , 2013 .

[15]  I. Tomeno,et al.  Magnetic neutron scattering study of ordered Mn3Ir , 1999 .

[16]  A. Kohn,et al.  The antiferromagnetic structures of IrMn3 and their influence on exchange-bias , 2013, Scientific Reports.

[17]  Wei Zhang,et al.  Spin Hall effects in metallic antiferromagnets. , 2014, Physical review letters.

[18]  A. Brataas,et al.  Spin-orbit torques in action. , 2014, Nature nanotechnology.

[19]  A. Panchula,et al.  Magnetically engineered spintronic sensors and memory , 2003, Proc. IEEE.

[20]  D. Ralph,et al.  Spin-Torque Switching with the Giant Spin Hall Effect of Tantalum , 2012, Science.

[21]  S. Parkin,et al.  Role of transparency of platinum–ferromagnet interfaces in determining the intrinsic magnitude of the spin Hall effect , 2015, 1504.07929.

[22]  Burke,et al.  Generalized Gradient Approximation Made Simple. , 1996, Physical review letters.

[23]  J. Sinova,et al.  An antidamping spin-orbit torque originating from the Berry curvature. , 2014, Nature nanotechnology.

[24]  A. Azevedo,et al.  Large inverse spin Hall effect in the antiferromagnetic metal Ir 20 Mn 80 , 2014 .

[25]  Malozemoff.  Random-field model of exchange anisotropy at rough ferromagnetic-antiferromagnetic interfaces. , 1987, Physical review. B, Condensed matter.

[26]  T. Higo,et al.  Large anomalous Hall effect in a non-collinear antiferromagnet at room temperature , 2015, Nature.

[27]  J. Pearson,et al.  All-electrical manipulation of magnetization dynamics in a ferromagnet by antiferromagnets with anisotropic spin Hall effects , 2015, 1508.07906.

[28]  Anomalous Hall effect arising from noncollinear antiferromagnetism. , 2013, Physical review letters.

[29]  A. Sakuma,et al.  First-principles study of the magnetic structures of ordered and disordered Mn-Ir alloys , 2003 .

[30]  C. Felser,et al.  Large anomalous Hall effect driven by a nonvanishing Berry curvature in the noncolinear antiferromagnet Mn3Ge , 2015, Science Advances.

[31]  L. M. Falicov,et al.  Magnetic Properties of Low-Dimensional Systems II , 1990 .

[32]  J. C. Sloncxewski,et al.  Current-driven excitation of magnetic multilayers , 2003 .

[33]  Dimitrie Culcer,et al.  Universal intrinsic spin Hall effect. , 2004, Physical review letters.

[34]  C. Kittel.  On the Theory of Ferromagnetic Resonance Absorption , 1948 .

[35]  S. Wimmer,et al.  Symmetry-imposed shape of linear response tensors , 2015, 1507.04947.

[36]  T. Higo,et al.  Large anomalous Hall effect in a non-collinear antiferromagnet at room temperature , 2016, Nature.

[37]  Parkin,et al.  Systematic variation of the strength and oscillation period of indirect magnetic exchange coupling through the 3d, 4d, and 5d transition metals. , 1991, Physical review letters.

[38]  H. Takahashi,et al.  Current-induced torques in structures with ultrathin IrMn antiferromagnets , 2015, 1503.03729.

[39]  J. Hirsch.  Spin Hall Effect , 1999, cond-mat/9906160.