373,347 research outputs found

    Anomalous Hall effect in non-collinear antiferromagnetic antiperovskite Mn3_{3}Ni1x_{1-x}Cux_{x}N

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    We report the anomalous Hall effect (AHE) in antiperovskite Mn3_{3}NiN with substantial doping of Cu on the Ni site (i.e. Mn3_{3}Ni1x_{1-x}Cux_{x}N), which stabilizes a noncollinear antiferromagnetic (AFM) order compatible with the AHE. Observed on both sintered polycrystalline pieces and single crystalline films, the AHE does not scale with the net magnetization, contrary to the conventional ferromagnetic case. The existence of the AHE is explained through symmetry analysis based on the Γ4g\Gamma_{\rm 4g} AFM order in Cu doped Mn3_{3}NiN. DFT calculations of the intrinsic contribution to the AHE reveal the non-vanishing Berry curvature in momentum space due to the noncollinear magnetic order. Combined with other attractive properties, antiperovskite Mn3_{3}AN system offers great potential in AFM spintronics.Comment: Supplemental Materials not include

    The anomalous Hall effect in non-collinear antiferromagnetic Mn3_{3}NiN thin films

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    We have studied the anomalous Hall effect (AHE) in strained thin films of the frustrated antiferromagnet Mn3_{3}NiN. The AHE does not follow the conventional relationships with magnetization or longitudinal conductivity and is enhanced relative to that expected from the magnetization in the antiferromagnetic state below TN=260T_{\mathrm{N}} = 260\,K. This enhancement is consistent with origins from the non-collinear antiferromagnetic structure, as the latter is closely related to that found in Mn3_{3}Ir and Mn3_{3}Pt where a large AHE is induced by the Berry curvature. As the Berry phase induced AHE should scale with spin-orbit coupling, yet larger AHE may be found in other members of the chemically flexible Mn3A_{3}AN structure

    Boston University Symphonic Chorus: Music for Chorus and Brass

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    This is the concert program of the Boston University Symphonic Chorus performance on Thursday, April 3, 1997 at 8:00 p.m., at the Tsai Performance Center, 685 Commonwealth Avenue. Works performed were Jubilate Deo, Plaudite, and In ecclesiis by Giovanni Gabrieli, Psalm 100, Die mit Thranen, and Selig sind die Toten by Heinrich Schutz, Nin danket alle Gott by Johann Pachelbel, Two Motets, "Offertorium" and "Ecce sacerdos" by Anton Bruckner, and To Saint Cecilia by Norman Dello Joio. Digitization for Boston University Concert Programs was supported by the Boston University Humanities Library Endowed Fund

    Bis(9-amino-acridinium) bis-(pyridine-2,6-dicarboxyl-ato-κO,N,O)nickelate(II) trihydrate.

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    The title compound, (C(13)H(11)N(2))(2)[Ni(C(7)H(3)NO(4))(2)]·3H(2)O, consists of a mononuclear anionic complex, two 9-amino-acridinium cations and three uncoordinated water mol-ecules. Two pyridine-2,6-dicarboxyl-ate (pydc) ligands are bound to the Ni(II) ion, giving an NiN(2)O(4) bonded set. The coordination geometry around the Ni(II) atom is distorted octa-hedral. There are two types of robust O-H⋯O hydrogen-bond synthons, namely R(6) (6)(24) and R(2) (4)(8), which link the complex anions and water mol-ecules to each other. N-H⋯O hydrogen bonds connect the stacks of anions and cations in the structure. Other inter-molecular inter-actions, including weak C-H⋯O hydrogen bonds, π-π [shortest centroid-centroid distance = 3.336 (7) Å] and C-O⋯π [O⋯centroid distance = 3.562 (10) Å] inter-actions, connect the various components

    ENSO dynamics: low-dimensional-chaotic or stochastic?

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    We apply a test for low-dimensional, deterministic dynamics to the Nino 3 time series for the El Nino Southern Oscillation (ENSO). The test is negative, indicating that the dynamics is high-dimensional/stochastic. However, application of stochastic forcing to a time-delay equation for equatorial-wave dynamics can reproduce this stochastic dynamics and other important aspects of ENSO. Without such stochastic forcing this model yields low-dimensional, deterministic dynamics, hence these results emphasize the importance of the stochastic nature of the atmosphere-ocean interaction in low-dimensional models of ENSO
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