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<jats:p>The quasiparticle interference (QPI) patterns of the superconducting state in Sr<jats:sub>2</jats:sub>RuO<jats:sub>4</jats:sub> are theoretically studied by taking into account the spin–orbital coupling and two different pairing modes, chiral p-wave pairing and equal d-wave pairing, in order to propose an experimental method to test them. Both of the QPI spectra for the two pairing modes have clearly peaks evolving with energy, and their locations can be determined from the tips of the constant energy contour. But the number, location, and evolution of these peaks with energy are different between the two pairing modes. The different behaviors of the QPI patterns in these two pairing modes may help to resolve whether Sr<jats:sub>2</jats:sub>RuO<jats:sub>4</jats:sub> is a chiral p-wave or d-wave superconductor.</jats:p>

<jats:p>We report <jats:sup>75</jats:sup>As-nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements on transition-metal arsenides LaRu<jats:sub>2</jats:sub>As <jats:sub>2</jats:sub>, KCa<jats:sub>2</jats:sub>Fe<jats:sub>4</jats:sub>As<jats:sub>4</jats:sub>F<jats:sub>2</jats:sub>, and <jats:italic>A</jats:italic> <jats:sub>2</jats:sub>Cr<jats:sub>3</jats:sub>As<jats:sub>3</jats:sub>. In the superconducting state of LaRu<jats:sub>2</jats:sub>As<jats:sub>2</jats:sub>, a Hebel–Slichter coherence peak is found in the temperature dependence of the spin-lattice relaxation rate 1/<jats:italic>T</jats:italic> <jats:sub>1</jats:sub> just below <jats:italic>T</jats:italic> <jats:sub>c</jats:sub>, which indicates that LaRu<jats:sub>2</jats:sub>As<jats:sub>2</jats:sub> is a full-gap superperconducor. For KCa<jats:sub>2</jats:sub>Fe<jats:sub>4</jats:sub>As<jats:sub>4</jats:sub>F<jats:sub>2</jats:sub>, antiferromagnetic spin fluctuations are observed in the normal state. We further find that the anisotropy rate <jats:inline-formula> <jats:tex-math><?CDATA ${R}_{{\rm{AF}}}={T}_{1}^{c}/{T}_{1}^{ab}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>R</mml:mi> <mml:mrow> <mml:mi mathvariant="normal">AF</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:msubsup> <mml:mi>T</mml:mi> <mml:mn>1</mml:mn> <mml:mi>c</mml:mi> </mml:msubsup> <mml:mo>/</mml:mo> <mml:msubsup> <mml:mi>T</mml:mi> <mml:mn>1</mml:mn> <mml:mrow> <mml:mi>a</mml:mi> <mml:mi>b</mml:mi> </mml:mrow> </mml:msubsup> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpb_29_6_067402_ieqn1.gif" xlink:type="simple" /> </jats:inline-formula> is small and temperature independent, implying that the low energy spin fluctuations are isotropic in spin space. Our results indicate that KCa<jats:sub>2</jats:sub>Fe<jats:sub>4</jats:sub>As<jats:sub>4</jats:sub>F<jats:sub>2</jats:sub> is a moderately overdoped iron-arsenide high-temperature superconductor with a stoichiometric composition. For <jats:italic>A</jats:italic> <jats:sub>2</jats:sub>Cr<jats:sub>3</jats:sub>As<jats:sub>3</jats:sub> (<jats:italic>A</jats:italic> = Na, K, Rb, Cs), we calculate the electric field gradient by first-principle method and assign the <jats:sup>75</jats:sup>As-NQR peaks to two crystallographically different As sites, paving the way for further NMR investigation.</jats:p>

<jats:p>The grain boundaries of graphene are disordered topological defects, which would strongly affect the physical and chemical properties of graphene. In this paper, the spectral characteristics and photoresponse of MoS<jats:sub>2</jats:sub>/graphene heterostructures are studied. It is found that the blueshift of the G and 2D peaks of graphene in Raman spectrum is due to doping. The lattice mismatch at the graphene boundaries results in a blueshift of MoS<jats:sub>2</jats:sub> features in the photoluminescence spectra, comparing to the MoS<jats:sub>2</jats:sub> grown on SiO<jats:sub>2</jats:sub>. In addition, the photocurrent signal in MoS<jats:sub>2</jats:sub>/hexagonal single-crystal graphene heterostructures is successfully captured without bias, but not in MoS<jats:sub>2</jats:sub>/polycrystalline graphene heterostructures. The electron scattering at graphene grain boundaries affects the optical response of MoS<jats:sub>2</jats:sub>/graphene heterostructures. The photoresponse of the device is attributed to the optical absorption and response of MoS<jats:sub>2</jats:sub> and the high carrier mobility of graphene. These findings offer a new approach to develop optoelectronic devices based on two-dimensional material heterostructures.</jats:p>

<jats:p>Large-scale Josephson junction (JJ) arrays are essential in many applications, especially quantum voltage standards application for which hundreds of thousands of junctions are required to realize a high quantum voltage. For almost all applications, high-quality JJ arrays must be realized in a small chip area. This study proposes vertically quadruple-stacked Nb/(Nb<jats:sub> <jats:italic>x</jats:italic> </jats:sub>Si<jats:sub>1 – <jats:italic>x</jats:italic> </jats:sub>/Nb)<jats:sub>4</jats:sub> JJs to increase the integration density of junctions in an array. The current–voltage (<jats:italic>I</jats:italic>–<jats:italic>V</jats:italic>) characteristics of a single stack of Nb/(Nb<jats:sub> <jats:italic>x</jats:italic> </jats:sub>Si<jats:sub>1 – <jats:italic>x</jats:italic> </jats:sub>/Nb)<jats:sub>4</jats:sub> JJs have been measured at 4.2 K. The uniformity of junctions in one stack and the uniformity of several stacks over the entire 2 inches wafer have been analyzed. By optimizing the fabrication parameters, a large-scale quadruple-stacked Nb/(Nb<jats:sub> <jats:italic>x</jats:italic> </jats:sub>Si<jats:sub>1 – <jats:italic>x</jats:italic> </jats:sub>/Nb)<jats:sub>4</jats:sub> array consisting of 400000 junctions is realized. Good DC <jats:italic>I</jats:italic>–<jats:italic>V</jats:italic> characteristics are obtained, indicating the good uniformity of the large-scale array.</jats:p>

<jats:p>The spin-1/2 Heisenberg chain coupled to a spin-<jats:italic>S</jats:italic> impurity moment with anti-periodic boundary condition is studied via the off-diagonal Bethe ansatz method. The twisted boundary breaks the <jats:italic>U</jats:italic>(1) symmetry of the system, which leads to that the spin ring with impurity can not be solved by the conventional Bethe ansatz methods. By combining the properties of the <jats:italic>R</jats:italic>-matrix, the transfer matrix, and the quantum determinant, we derive the <jats:italic>T</jats:italic>–<jats:italic>Q</jats:italic> relation and the corresponding Bethe ansatz equations. The residual magnetizations of the ground states and the impurity specific heat are investigated. It is found that the residual magnetizations in this model strongly depend on the constraint of the topological boundary condition, the inhomogeneity of the impurity comparing with the hosts could depress the impurity specific heat in the thermodynamic limit. This method can be expand to other integrable impurity models without <jats:italic>U</jats:italic>(1) symmetry.</jats:p>

<jats:p>We report the physical properties, crystalline and magnetic structures of singe crystals of a new layered antiferromagnetic (AFM) material PrPd<jats:sub>0.82</jats:sub>Bi<jats:sub>2</jats:sub>. The measurements of magnetic properties and heat capacity indicate an AFM phase transition at <jats:italic>T</jats:italic> <jats:sub>N</jats:sub> ∼ 7 K. A large Sommerfeld coefficient of 329.23 mJ⋅mol<jats:sup>−1</jats:sup>⋅K<jats:sup>−2</jats:sup> is estimated based on the heat capacity data, implying a possible heavy-fermion behavior. The magnetic structure of this compound is investigated by a combined study of neutron powder and single-crystal diffraction. It is found that an A-type AFM structure with magnetic propagation wavevector <jats:italic> <jats:bold>k</jats:bold> </jats:italic> = (0 0 0) is formed below <jats:italic>T</jats:italic> <jats:sub>N</jats:sub>. The Pr<jats:sup>3+</jats:sup> magnetic moment is aligned along the crystallographic <jats:italic>c</jats:italic>-axis with an ordered moment of 1.694(3) <jats:italic>μ</jats:italic> <jats:sub>B</jats:sub> at 4 K, which is smaller than the effective moment of the free Pr<jats:sup>3+</jats:sup> ion of 3.58 <jats:italic>μ</jats:italic> <jats:sub>B</jats:sub>. PrPd<jats:sub>0.82</jats:sub>Bi<jats:sub>2</jats:sub> can be grown as large as 1 mm×1 cm in area with a layered shape, and is very easy to be cleaved, providing a unique opportunity to study the interplay between magnetism, possible heavy fermions, and superconductivity.</jats:p>

<jats:p>The critical properties and the nature of the ferromagnetic–paramagnetic phase transition in the 2D organic-inorganic hybrid (CH<jats:sub>3</jats:sub>NH<jats:sub>3</jats:sub>)<jats:sub>2</jats:sub>CuCl<jats:sub>4</jats:sub> single crystal have been investigated by dc magnetization in the vicinity of the magnetic transition. Different techniques were used to estimate the critical exponents near the ferromagnetic–paramagnetic phase transition such as modified Arrott plots, the Kouvel–Fisher method, and the scaling hypothesis. Values of <jats:italic>β</jats:italic> = 0.22, <jats:italic>γ</jats:italic> = 0.82, and <jats:italic>δ</jats:italic> = 4.4 were obtained. These critical exponents are in line with their corresponding values confirmed through the scaling hypothesis as well as the Widom scaling relation, supporting their reliability. It is concluded that this 2D hybrid compound possesses strong ferromagnetic intra-layer exchange interaction as well as weak interlayer ferromagnetic coupling that causes a crossover from 2D to 3D long-range interaction.</jats:p>

<jats:p>One-port magnetic surface acoustic wave (MSAW) resonators are fabricated by stacking multilayered (FeCoSiB/SiO<jats:sub>2</jats:sub>)<jats:sub> <jats:italic>n</jats:italic> </jats:sub> films directly on top of interdigital electrodes. It is shown that the magneto-acoustic response of the MSAW resonators critically depends the hysteresis of Δ<jats:italic>E</jats:italic> effect. For the magnetic multilayer without induced magnetic anisotropy, the resonance frequency (<jats:italic>f</jats:italic> <jats:sub>R</jats:sub>) exhibits a butterfly-like dependence on the external field, therefore, enabling bipolar detection of magnetic field smaller than its coercive field. However, for the magnetic multilayers with induced magnetic anisotropy, butterfly-like or loop-like <jats:italic>f</jats:italic> <jats:sub>R</jats:sub>–<jats:italic>H</jats:italic> curves are measured along the interdigtial electrode fingers or the SAW propagation direction, which can be attributed to the competition between the magnetic field-induced anisotropy and the stress-induced or shape anisotropy.</jats:p>

<jats:p>Nowadays the yttrium iron garnet (Y<jats:sub>3</jats:sub>Fe<jats:sub>5</jats:sub>O<jats:sub>12</jats:sub>, YIG) films are widely used in the microwave and spin wave devices due to their low damping constant and long propagation distance for spin waves. However, the performances, especially the frequency stability, are seriously affected by the relaxation of the interface magnetic moments. In this study, the effect of out-of-plane magnetization depinning on the resonance frequency shift (Δ<jats:italic>f</jats:italic> <jats:sub>r</jats:sub>) was investigated for 3-μm YIG films grown on Gd<jats:sub>3</jats:sub>Ga<jats:sub>5</jats:sub>O<jats:sub>12</jats:sub> (GGG) (111) substrates by liquid-phase epitaxy. It is revealed that the ferromagnetic resonance (FMR) and spin wave propagation exhibit a very slow relaxation with relaxation time <jats:italic>τ</jats:italic> even longer than one hour under an out-of-plane external magnetic bias field. The Δ<jats:italic>f</jats:italic> <jats:sub>r</jats:sub> span of 15.15–24.70 MHz is observed in out-of-plane FMR and forward volume spin waves. Moreover, the Δ<jats:italic>f</jats:italic> <jats:sub>r</jats:sub> and <jats:italic>τ</jats:italic> depend on the magnetic field. The Δ<jats:italic>f</jats:italic> <jats:sub>r</jats:sub> can be attributed to that the magnetic moments break away from the pinning layer at the YIG/GGG interface. The thickness of the pinning layer is estimated to be about 9.48 nm to 15.46 nm according to the frequency shifting. These results indicate that Δ<jats:italic>f</jats:italic> <jats:sub>r</jats:sub> caused by the pinning layer should be addressed in the design of microwave and spin wave devices, especially in the transverse magnetic components.</jats:p>

<jats:p>The SrFe<jats:sub>12</jats:sub>O<jats:sub>19</jats:sub>@carbonyl iron (CI) core–shell composites used in microwave absorption are prepared by the metal–organic chemical vapor deposition (MOCVD). The x-ray diffractometer, scanning electron microscope, energy dispersive spectrometer, and vector network analyzer are used to characterize the structural, electromagnetic, and absorption properties of the composites. The results show that the SrFe<jats:sub>12</jats:sub>O<jats:sub>19</jats:sub>@CI composites with a core–shell structure could be successfully prepared under the condition: deposition temperatures above 180 °C, deposition time 30 min, and gas flow rate 30 mL/min. The electromagnetic properties of the composites change significantly, and their absorption capacities are improved. Of the obtained samples, those samples prepared at a deposition temperature of 180 °C exhibit the best absorption performance. The reflection loss of SrFe<jats:sub>12</jats:sub>O<jats:sub>19</jats:sub>@CI (180 °C) with 1.5 mm–2.5 mm in thickness is less than −10 dB in a frequency range of 8 GHz–18 GHz, which covers the whole X band and Ku band.</jats:p>