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Interfacial magnetic anisotropy in magnetic insulators has been largely unexplored. Recently, interface-induced skyrmions and electrical control of magnetization have been discovered in insulator-based heterostructures, which demand a thorough understanding of interfacial interactions in these materials. We observe a substantial, tunable interfacial magnetic anisotropy between Tm_{3}Fe_{5}O_{12} epitaxial thin films and fifteen nonmagnetic materials spanning a significant portion of the periodic table, which we attribute to Rashba spin-orbit coupling. Our results show a clear distinction between nonmagnetic capping layers from the d block and the p block. This work offers a new path for controlling magnetic phases in magnetic insulators for low-loss spintronic applications.

We demonstrate nondecaying, steplike electrical switching of tristate N\'eel order in $\mathrm{Pt}/\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{Fe}}_{2}{\mathrm{O}}_{3}$ bilayers detected by the spin-Hall induced anomalous Hall effect. The as-grown $\mathrm{Pt}/\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{Fe}}_{2}{\mathrm{O}}_{3}$ bilayers exhibit sawtooth switching behavior generated by current pulses. After annealing by a high pulse current, the Hall signals reveal single-pulse saturated, nondecaying, steplike switching. Together with control experiments, we show that the sawtooth switching is due to an artifact of Pt while the actual spin-orbit torque induced antiferromagnetic switching is steplike. Our Monte Carlo simulations explain the switching behavior of $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{Fe}}_{2}{\mathrm{O}}_{3}$ N\'eel order among three in-plane easy axes.

The topological Hall effect has been a primary indicator of nontrivial spin textures in magnetic materials. We observe the evidence of the topological Hall effect in $\mathrm{Pt}/{\mathrm{Cr}}_{2}{\mathrm{O}}_{3}$ bilayers grown on ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}(0001)$ and ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}(11\overline{2}0)$, where the ${\mathrm{Cr}}_{2}{\mathrm{O}}_{3}$ epitaxial film is an antiferromagnetic insulator. The $\mathrm{Pt}/{\mathrm{Cr}}_{2}{\mathrm{O}}_{3}$ bilayers exhibit topological Hall resistivity for ${\mathrm{Cr}}_{2}{\mathrm{O}}_{3}$ thicknesses below 6 nm near and above room temperature, which is above the N\'eel temperature of ${\mathrm{Cr}}_{2}{\mathrm{O}}_{3}$, revealing the key role of thermal fluctuations in the formation of spin textures. The similarity of topological Hall signals in (0001)- and $(11\overline{2}0)$-oriented ${\mathrm{Cr}}_{2}{\mathrm{O}}_{3}$ films indicates that the emergence of spin textures is insensitive to crystalline orientation.

We demonstrate nondecaying, steplike electrical switching of tristate Néel order in Pt/α-Fe_{2}O_{3} bilayers detected by the spin-Hall induced anomalous Hall effect. The as-grown Pt/α-Fe_{2}O_{3} bilayers exhibit sawtooth switching behavior generated by current pulses. After annealing by a high pulse current, the Hall signals reveal single-pulse saturated, nondecaying, steplike switching. Together with control experiments, we show that the sawtooth switching is due to an artifact of Pt while the actual spin-orbit torque induced antiferromagnetic switching is steplike. Our Monte Carlo simulations explain the switching behavior of α-Fe_{2}O_{3} Néel order among three in-plane easy axes.

Noncollinear antiferromagnet Mn3Sn has attracted wide interest as it is a candidate for Weyl semimetal. Here, we report the observation of topological Hall like signals in Mn3Sn/Pt bilayers grown on Al2O3(0001). X-ray diffraction and scanning transmission electron microscopy results confirm the high epitaxial quality of the c-axis-oriented Mn3Sn films. The detected topological Hall resistivity shows a broad temperature range from 210 to 365 K by tuning the thickness of Mn3Sn from 3 to 15 nm. Compared with previously reported topological Hall effects in Mn3Sn at temperatures below 50 K, the observed high-temperature topological Hall signal is likely due to the stabilization of topological spin textures enabled by the strong spin–orbit coupling of the Pt overlayer and the Dzyaloshinskii–Moriya interaction at the Mn3Sn/Pt interface.

The unique optical properties of TPs – such as flexible wavevector matching conditions including in-plane wavevector within the light line, existing both S- and P-polarized TPs and ability of populating with KR and RK illuminations – facilitate them for direct optical excitation. The Tamm plasmon Coupled emission (TPCE) from a combined photonic-plasmonic structure sustaining both surface plasmons (SPs) and Tamm plasmons (TPs) is described. The sensitivity of TPCE to the emission wavelength and polarization is examined with back focal plane imaging and verified with the numerical calculations. The results reveal that the excited probe can couple with both TPs and SPs, resulting in SPCE and TPCE, respectively. The TPCE angle is strongly dependent on the wavelength allowing for spectral resolution using different observation angles. These Tamm structures provide a new tool to control the optical emission from dye molecules and have many potential applications in fluorescence based-sensing and imaging.

We measure the spin Hall angle in Au layers of 5--100 nm thicknesses by spin pumping from ${\mathrm{Y}}_{3}\mathrm{F}{\mathrm{e}}_{5}{\mathrm{O}}_{12}$ epitaxial films grown by ultrahigh vacuum, off-axis sputtering. We observe a striking increase in the spin Hall angle for Au layers thinner than the measured spin diffusion length of 12.6 nm. In particular, the 5 nm Au layer shows a large spin Hall angle of 0.087, compared to those of 0.016 and 0.017 for the 50 and 100 nm Au layers, respectively, suggesting that the top surface plays a dominant role in spin Hall physics when the spin current is able to reach it. Other spin pumping related parameters, including Gilbert damping enhancement, interfacial spin mixing conductance, and spin current are also determined for Au layers of various thicknesses. Given the pervasive role of ultrathin films in electrical and spin transport applications, this result emphasizes the importance of considering the impact of the top surface and reveals the possibility of tuning critical spin parameters by film thickness.

The unique optical properties of TPs – such as flexible wavevector matching conditions including in-plane wavevector within the light line, existing both S- and P-polarized TPs and ability of populating with KR and RK illuminations – facilitate them for direct optical excitation. The Tamm plasmon Coupled emission (TPCE) from a combined photonic-plasmonic structure sustaining both surface plasmons (SPs) and Tamm plasmons (TPs) is described. The sensitivity of TPCE to the emission wavelength and polarization is examined with back focal plane imaging and verified with the numerical calculations. The results reveal that the excited probe can couple with both TPs and SPs, resulting in SPCE and TPCE, respectively. The TPCE angle is strongly dependent on the wavelength allowing for spectral resolution using different observation angles. These Tamm structures provide a new tool to control the optical emission from dye molecules and have many potential applications in fluorescence based-sensing and imaging.

We report spin-echo double resonance NMR measurements of {sup 17}O- {sup 63} Cu indirect (electron-mediated) nuclear spin-spin coupling between Cu and O atoms in the CuO{sub 2} planes of YBa{sub 2}Cu {sub 3}O{sub 7} . The magnitude of the measured coupling is anomalously large, to the extent that it is inconsistent with the antiferromagnetic correlations that are invoked to explain the contrasting T{sub 1} behaviors of {sup 63}Cu and {sup 17}O . {copyright} {ital 1999} {ital The American Physical Society }

We report a simple NMR experiment measuring individual ${}^{63}\mathrm{Cu}\ensuremath{-}{}^{63}\mathrm{Cu}$ indirect nuclear coupling frequencies in $\mathrm{YBa}{}_{2}\mathrm{Cu}{}_{3}{\mathrm{O}}_{7}$. We show that the coupling interaction at $T\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}5\mathrm{K}$ is of quite short range, indicating an anitferromagnetic correlation length $\ensuremath{\xi}$ of $\ensuremath{\sim}1$ lattice constant or less.

A priori theoretical considerations lead one to expect that ${\mathrm{Rb}}_{3}{\mathrm{C}}_{60}$ is a Mott-Hubbard insulator. This has led to the proposal that the superconductor `` ${\mathrm{Rb}}_{3}{\mathrm{C}}_{60}$'' is, in fact, ${\mathrm{Rb}}_{3\ensuremath{-}\ensuremath{\varepsilon}}{\mathrm{C}}_{60}$ $(\ensuremath{\varepsilon}\ensuremath{\sim}0.06)$, and, furthermore, that the vacancies are associated with an unexpected, robust splitting in ${}^{87}\mathrm{Rb}$ NMR. We demonstrate that vacancies, if present, are unrelated to observed NMR splittings.

The saturation magnetization of Y3Fe5O12 (YIG) epitaxial films 4 to 250 nm in thickness has been determined by complementary measurements including the angular and frequency dependencies of the ferromagnetic resonance fields as well as magnetometry measurements. The YIG films exhibit state-of-the-art crystalline quality, proper stoichiometry, and pure Fe3+ valence state. The values of YIG magnetization obtained from all the techniques significantly exceed previously reported values for single crystal YIG and the theoretical maximum. This enhancement of magnetization, not attributable to off-stoichiometry or other defects in YIG, opens opportunities for tuning magnetic properties in epitaxial films of magnetic insulators.

Bloch surface waves (BSWs) on one-dimensional photonic crystals (1DPC) have been used to beam the fluorescence emission from the dye molecules. All dielectric 1DPC displays its low propagating loss, narrow resonance and the absence of absorption or quenching. In this letter, back focal plane imaging reveals that in addition to the BSW mode, a guided mode and cavity mode also exist in the 1DPC which all couple with the excited dye molecules. The appearance of these modes is sensitive to the wavelength of the fluorescence and alters the beaming effect by the 1DPC. Numerical simulations verify the existence of these modes which are consistent with the experimental results. Comparisons between the Bloch surface wave-coupled emission (BWCE) and surface plasmon-coupled emission (SPCE) are also presented for a more clear understanding of the multilayered film-enabled directional emission.