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We report the observation of unidirectional magnetoresistance (UMR) in the ferrimagnetic insulator CoFe2O4(CFO)/Pt heterostructures, which stem from the giant interfacial Rashba–Edelstein effect. Furthermore, UMR has been found to show sign reversal and amplitude enhancement characteristics with decrease in temperature. We have ascribed it to the modulated distortion of Fermi contours due to pronounced spin canting at low temperatures. The presence of spin canting induced interfacial magnetic state has also been demonstrated by spin Hall magnetoresistance in CFO/Pt/Co/Al2O3 films. Our work reveals the interfacial magnetic state modulated UMR in CFO/Pt bilayers, thereby paving the way for extending its applications in ferrimagnet-based spintronic devices. [ABSTRACT FROM AUTHOR]

We have observed robust chiral spin torques and non-reciprocal charge transport behaviors in the α-Fe2O3/Pt bilayers through a combination of magnetic field and current-dependent second longitudinal harmonic resistance measurements. The interfacial Dzyaloshinskii–Moriya interaction induced magnetic chirality has been predicted to account for the sign reversal characteristic of the second longitudinal harmonic resistance with increasing the current amplitude. A physical model that considers the chirality dependence of both the asymmetric scattering and the giant Rashba spin–orbit coupling has been set up to uncover the microscopic interactions between charge, spin, and magnetic chirality. Our comprehensive approach leverages the semiclassical Boltzmann theory to validate the consistency between this model and our experimental findings. Through our investigation, we have established the pivotal role of interfacial magnetic chirality in determining both charge and spin transport behaviors within antiferromagnetic insulator/heavy metal bilayer systems. Our work not only enhances the comprehension of spin–orbit torques and non-reciprocal charge transport but also contributes to the broader understanding of these phenomena. The outcomes of this study have broader implications for the advancement of spintronics and related fields. [ABSTRACT FROM AUTHOR]

In this work, we have prepared an antiferromagnetic insulated α-Fe2O3 film with a large out-of-plane magnetic component and studied the spin Hall magnetoresistance (SMR) in α-Fe2O3/Pt bilayers. Both angular-dependent magnetoresistance and field-dependent magnetoresistance have featured a sign change characteristic with varying temperature, which is ascribed to the competition between a modulated interface magnetic state and an antiferromagnetic bulk state of the α-Fe2O3 film. According to a generalized theoretical model, which takes the effective spin conductance into consideration, the spin transport can be mathematically expressed as the change of field dependent average spin operators with varying temperature. The critical temperature also depends on the α-Fe2O3 film thickness and the magnetic field, which are ascribed to the magnons transport and long-range order of non-collinear spin textures, respectively. Furthermore, we have given a phenomenological form to fit the SMR curves in the critical temperature interval, which further reveals the origin of SMR with complex magnetic structures. [ABSTRACT FROM AUTHOR]

We have investigated the spin Hall magnetoresistance (SMR) in CoFe2O4/Pt heterostructures deposited on (001) MgO and (001) MgAl2O4 substrates, respectively. It is found that the interface non-collinear magnetic configurations should exist in both of the two films in the whole temperature range from 5 to 300 K but mainly dominate the spin transport properties at low temperature. Furthermore, the spin transport has featured epitaxial-strain-modified characteristics induced by different substrates, which has been investigated by magnetic curves, SMR, anisotropic magnetoresistance, and Hall effect measurements. [ABSTRACT FROM AUTHOR]

Thin films of Bi1.05La0.05FeO3 (BLFO) have been deposited on a CaRuO3 buffering layer on SrTiO3 using pulsed laser deposition. Then, a Pt thin layer was in situ sputtered on the surface of BLFO. The crystallization characteristic and surface morphology of the BLFO layer were checked. Spin transporting behaviors of the Pt/BLFO structure were investigated at room temperature. Interestingly, a magnetoresistance effect was observed at the interface of the Pt/BLFO bilayer. The spin mixing conductance at the interface between BLFO and Pt was estimated after a corrections of Pt thickness. This implies that the manipulation of spin–orbit coupling is possible at the interface of a single-phase multiferroic (e.g., BLFO) and a heavy metal (e.g., Pt). [ABSTRACT FROM AUTHOR]

Nonreciprocal charge transport, which is frequently termed as electrical magnetochiral anisotropy (EMCA) in chiral conductors, touches the most important elements of modern condensed matter physics. Here, we have investigated the large EMCA in Pt/PtMnGa (PMG) bilayers, which can be attributed to the nonreciprocal response of an interface-driven chiral transport channel. Different from the traditional linear current-dependent EMCA, for Pt/PMG bilayers, higher-order EMCA coefficients should be phenomenally added especially for the small current region. This unusual behavior has been explained based on both quantum transport and semiclassical transport models. Furthermore, a combination of asymmetrical electron scattering and spin-dependent scattering furnish the PMG thickness-dependent chiral transport behaviors in Pt/PMG bilayers. The dramatically enhanced anomalous Hall angle of PMG further demonstrates the modified surface state properties by strong spin–orbit coupling. [ABSTRACT FROM AUTHOR]

To investigate the reason for the reduction in damage resistance of InxGa1−xN with increasing indium (In) content, we used molecular dynamics methods to simulate the threshold displacement energies, the individual recoil damage and the overlapping cascade processes in InxGa1−xN (x = 0.3, 0.5, 0.7) during ion implantation. The average threshold displacement energy of InxGa1−xN decreases a little (from 41.0 eV to 34.6 eV) as the In content increases (from 0.3 to 0.7) and the number of defects produced by individual cascades increases less than 30% with increasing In content (from 0.3 to 0.7), while the overlapping cascade simulations showed that with In content increasing the dynamic annealing processes in cascades were significantly suppressed. Thus, the suppression of dynamic annealing in the cascades is the main reason for the reduction of damage resistance of InxGa1−xN by adding In content. The analysis of defect distribution during overlapping cascades showed that defects in In-rich InxGa1−xN (x = 0.7) agglomerate more rapidly as the irradiation dose increases and are likely to form large clusters, which are harder to anneal during cascade evolution. Therefore, the suppression of dynamic annealing in In-rich InxGa1−xN can be attributed to the rapid agglomeration of defects with the irradiation dose. [ABSTRACT FROM AUTHOR]

The spin-mixing conductance (SMC) is an essential parameter for ferromagnetic-insulators-based spintronics devices. Here, we study the influence of device boundary on local spin transport properties in platinum (Pt)/yttrium iron garnet (YIG) films by reducing the lateral size of the devices. An obvious fluctuation of spin Hall magnetoresistance, Gilbert damping coefficient, and effective spin Hall angle with restricting the size of YIG films has been found at room temperature. By employing both harmonic and current-induced spin-torque ferromagnetic resonance measurements, we have found a negligible fluctuation of both the imaginary part of SMC and effective magnetization with varying the geometric size of devices. In contrast, the real part of SMC at the Pt/YIG interface has been rigidly altered. Our results show that the SMC dramatically depends on the boundary effect from Ar+-ion milling. [ABSTRACT FROM AUTHOR]

The magnetization dynamics of disordered Fe0.5(Pd1-xPtx)0.5 alloy films was studied by time-resolved magneto-optical Kerr effect and ferromagnetic resonance. The intrinsic Gilbert damping parameter α0 and the resonance linewidth change linearly with the Pt atomic concentration. In particular, the induced in-plane uniaxial anisotropy constant KU also increases for x increasing from 0 to 1. All these results can be attributed to the tuning effect of the spin orbit coupling. For the disordered ternary alloys, an approach is proposed to control the induced in-plane uniaxial anisotropy, different from conventional thermal treat methods, which is helpful to design and fabrications of spintronic devices. [ABSTRACT FROM AUTHOR]

We have studied the magneto-optical Kerr effect (MOKE) of L10 Fe0.5(Pd1-xPtx)0.5 alloy films with both experiments and first-principles calculations. In the visible region, negative Kerr rotation and ellipticity peaks are, respectively, observed in the regions of 1.5-2.0 eV and 1.7-2.6 eV. These peaks are shifted towards higher energies, and their magnitudes are enhanced for larger x. The MOKE evolution is mainly ascribed to the anomalous Hall conductivity contributed by the spin-down d↓;x2-y2 bands from Pd and Pt. We established a close correlation among the MOKE spectra, the spin orbit coupling strength, and the band feature for this prototypical system. [ABSTRACT FROM AUTHOR]

We report spin–orbit torques (SOT) in a L10-ordered perpendicularly magnetized FePt single layer, which is significantly influenced by disorder. Recently, self-induced SOT in the L10-FePt single layer has been investigated, which is ascribed to the composition gradient along the normal direction of the film. However, the determined mechanisms for magnetization switching have not been fully studied. With varying growth temperatures, we have prepared FePt single layers with the same thickness (3 nm) but with different disordering. We have found that nearly full magnetization switching only happens in more disordered films, and the magnetization switching ratio becomes smaller with increasing L10 ordering. The method for deriving effective spin torque fields in the previous studies cannot fully explain the spin current generation and self-induced SOT in the L10-FePt single layer. Combined with the magneto-optical Kerr effect microscopy and anomalous Hall effect measurements, we concluded that the disorder should determine the formation of domain walls, as well as the spin current generation. [ABSTRACT FROM AUTHOR]

The spin currents generated by spin–orbit coupling in nonmagnetic metals or at interfaces with broken inversion symmetry are particularly important for devices with extraordinary performance. We have investigated the spin–orbit torques (SOTs) in Ru/Fe/HfO2 heterostructures with weak perpendicular magnetic anisotropy. Although the bulk spin Hall effect (SHE) of the Ru layer is smaller than that of Pt, Ta, or W, robust SOT-induced magnetization switching can also be realized. Through nonadiabatic harmonic measurements, the effective spin Hall angle in Ru/Fe/HfO2 heterostructures is calculated to be −0.045. We have explored the mechanisms of spin current generation, which could stem from the Ru/Fe interfaces other than the weak bulk SHE of Ru. Our results suggest the spin current generation mechanisms in ferromagnet/nonmagnetic metal heterostructures remain to be further explored. [ABSTRACT FROM AUTHOR]

In order to overcome the difficulty in obtaining the initial shallow groundwater level of a small bedrock island and build a better geological body model, the assessment of groundwater potential by remote sense (RS) method was introduced into the shallow groundwater flow field modeling of bedrock islands. And the Wailingding Island in China was taken as the study area. The buried depth (h) of water level was fitted with the remote sensing assessment score of shallow groundwater potential, according to the actual water volume. As a result, the study obtained the formula of the fitting curve, which was S=0.427e0.239h, R2=0.8462 (P<0.05). Then, it used ENVI software to calculate h=(1/0.239) ln(S/0.427) and evaluate the initial water level of shallow groundwater: D= DEM-h. Moreover, the study introduced the value of D into the GMS software as the initial water level for the simulation of the shallow groundwater flow field, overcoming the difficulty in obtaining the water level of shallow groundwater in the bedrock islands. The GMS software was used to establish a simulation model of shallow groundwater flow field based on the hydrogeological data in this study area. Also, it used ENVI software to convert DEM data into TIF files and import them into the GMS software, improving the precision of island geological body simulation. Next, the study attempted to change the initial conditions of the simulation model of the shallow groundwater flow field, such as rainfall, evaporation capacity and so on, to predict the distribution of shallow groundwater flow field at different times. Finally, the actual water yield of springs and wells and the geophysical data were used to verify the results of the simulation, and the accuracy has met the requirement. Therefore, it is possible complete the simulation of the shallow groundwater flow field of a small bedrock island by RS technology and other techniques. [ABSTRACT FROM AUTHOR]

The transport properties of a graphene multiquantum well system are investigated numerically using transfer-matrix method. There are transmission gaps for electrons and holes in the transmission spectra at tilted incidence. In the transmission gaps, a few resonant tunneling peaks appear, defined as transmission windows, which are related with the bound states in the quantum wells. Unlike conventional semiconductor nanostructures, the location and the width of the transmission windows are sensitive not only to the quantum well width but also the incident angle. The number of the quantum wells determines the fine structure of the transmission windows. The anisotropic property is affected in the following way: the increase in well width makes the nonzero-transmission incident angle range decrease, and the interference effect is enhanced as the well number increases. Tiny oscillation of the conductance and fine structures in the middle energy range are due to the resonant tunneling induced by the multiquantum well structure. These oscillating features may be helpful in explaining the oscillatory characteristics in experiment. [ABSTRACT FROM AUTHOR]

Heusler alloy Co2FeAl was employed as ferromagnetic layers in Co2FeAl (3 nm)/Ru (x nm)/Co2FeAl (5 nm) synthetic antiferromagnet structures. The experimental results show that the structure with a Ru thickness of 0.45 nm is strongly antiferromagnetic coupled, which is maintained after annealing at 150 °C for 1 h. The structure has a very low saturation magnetization Ms of 425 emu/cm3, a low switching field Hsw of 4.3 Oe, and a high saturation field Hs of 5257 Oe at room temperature, which are favorable for application in ultrahigh density magnetic read heads or other magnetic memory devices. Crystal structure study testifies that the as-deposited Co2FeAl film is in the B2 phase. Therefore, Heusler alloys can be used to fabricate synthetic antiferromagnetic and it is possible to make “all-Heusler” spin valves or magnetic tunneling junctions with better magnetic switching properties and high magnetoresistance. [ABSTRACT FROM AUTHOR]

A large single crystal of barium tungstate (BaWO4) with dimensions of 22-mm diameter×80-mm length was grown by the Czochralski method using an iridium crucible. The melting point, molar enthalpy of fusion, and molar entropy of fusion of the crystal were determined to be 1775.10 K, 96 913.80 J mol-1, and 54.60 J K-1 mol-1, respectively. The average linear thermal-expansion coefficients are αa=10.9526×10-6/K, αb=10.8069×10-6/K, and αc=35.1063×10-6/K in the temperature range from 303.15 to 1423.15 K along the three respective crystallographic axes. The density of the crystal follows an almost linear decrease from 6.393×103 to 6.000×103 kg m-3 when the temperature is increased from 303.15 to 1423.15 K. The measured specific heat are 115.56–130.96 J K-1 mol-1 in the temperature range of 323.15–1173.15 K. The thermal diffusion coefficient of the crystal was measured in the temperature range of 297.15–563.15 K. The calculated thermal conductivity is 2.256 W m-1 K-1 along the [001] direction and 2.324 W m-1 K-1 along the [100] direction at 323.15 K. The microhardness of the BaWO4 single crystal in the (001) and (100) planes is 1393 and 1814 MPa under a load of 0.050 kg. [ABSTRACT FROM AUTHOR]

We study the spin Hall magnetoresistance (SMR) in a Cr2O3/Ta bilayer with a buffered TaOx layer. Comparing the temperature dependence of SMR in Cr2O3 without a TaOx buffer layer, an additional change of sign is observed at 95 K. By means of the analysis of structure and magnetism, the amorphous properties and surface magnetic frustration are responsible for the change of sign in SMR. Our results demonstrate that the transport performance could be used to explore the magnetic textures at the complex interface of antiferromagnet/non-magnetic metal bilayers. Thus, SMR might become a characteristics tool in the field of antiferromagnetic spintronics. [ABSTRACT FROM AUTHOR]

Summary: Background: Various trials have been conducted on the management of male pattern hair loss (MPHL), but the outcomes often seem to be limited. Adjuvant therapies are urgently needed. Aim: To evaluate the efficacy and safety of combined fractional radiofrequency microneedling (FRM) and 5% topical minoxidil in the treatment of male pattern hair loss. Methods: In total, 19 Chinese men were enrolled in this randomized, controlled, split‐scalp trial. Participants received monotherapy with 5% topical minoxidil twice daily to one half of the scalp, while on the other half of the scalp the treatment with twice‐daily 5% topical minoxidil was combined with five sessions of FRM at 4‐week intervals. Mean hair count and hair thickness, global assessment by the investigators, subject self‐assessment and adverse effects were assessed. Results: After 5 months of treatment, mean hair count increased from 44.12 ± 21.58 to 73.14 ± 25.45 on the combined‐therapy side and from 46.22 ± 18.77 to 63.21 ± 19.22 on the monotherapy side, while mean hair thickness increased from 53 ± 13 μm to 71 ± 15 μm and from 52 ± 16 μm to 66 ± 14 μm, respectively. Compared with the monotherapy side, the combined‐therapy side had a higher degree of improvement in both hair count (P = 0.01) and hair thickness (P = 0.02). Conclusions: Combined treatment with fractional radiofrequency microneedle and 5% topical minoxidil could be an effective and safe treatment option for male pattern hair loss. [ABSTRACT FROM AUTHOR]

Magnetism control has a variety of applications in magnetic storage and spintronic devices. Instead of the control of direct magnetoelectric coupling via strain, voltage, and Dzyaloshinskii-Moriya interaction, the polarization-dependent coupling in multiferroic materials such as BiFeO3 is employed for the electric-field control of magnetizations in this work. A perpendicular magnetic anisotropy (PMA) has been realized in a BiFeO3/Al2O3/Pt/Co/Pt multiferroic structure at room temperature. Interestingly, a distinct change of coercivity field (∼400%) has been observed in the structure with opposite polarization directions, which can be attributed to the different oxidation degree at the Pt/Co interface. This spontaneous polarization-controlled switching not only provides us a platform to study the interfacial effect in multiferroic heterostructures but also paves the way to manipulate PMA or even spin orbit torque through oxygen vacancies. [ABSTRACT FROM AUTHOR]

We demonstrate the negative spin Hall magnetoresistance (SMR) observed in antiferromagnetic Cr2O3/Ta bilayers at low temperature. The SMR signals are changed from the positive to negative magnitude when monotonously reducing the temperature from 300 K to 50 K. The positive and negative SMR signals are expected to be associated with the two different ways for injection of the spin current, into the boundary ferromagnetic region and the bulk antiferromagnetic region of α-Cr2O3 (0001), respectively. The slopes of the abnormal Hall curves exhibit the same sign with the SMR signal. From the SMR ratio under 3 T, the spin mixing conductance at the Cr2O3/Ta interface is estimated to be 1.12 × 1014 Ω−1·m−2, which is comparable to the one observed in the Y3Fe5O12(YIG)/Pt structure and our early results of the Cr2O3/W structure. [ABSTRACT FROM AUTHOR]

The spin Hall magnetoresistance (SMR) effect is studied in a magnetoelectric Cr2O3/heavy-metal W heterostructure. The Cr2O3 film is confirmed as the α-phase, and its Néel temperature is determined. A clear SMR behavior is observed at the interface of Cr2O3/W. A nearly 0.1% SMR ratio is achieved under a magnetic field of 9 T, which is larger than the reported value in the SrMnO3/Pt structure. A systematic study on the variations of SMR as functions of the magnetic field and its angle is performed. Our results indicate that the antiferromagnetic magnetoelectric Cr2O3/W structure has a promising prospect application in future spintronic devices. [ABSTRACT FROM AUTHOR]

This paper presents a novel stall detection method based on symmetrized dot pattern (SDP) analysis, which detects the starting point of rotating stall timely and accurately during operations of centrifugal fans. To demonstrate the proposed method, experiments were first performed on a G4-73 No. 8D centrifugal fan to measure the aerodynamic pressure signals of the air flow inside the fan during the gradual development of rotating stall. Then, the SDP technique was used to analyze the pressure signals and extract the time-domain characteristics of the pressure signal during the gradual development of rotation stall. Finally, a comprehensive autocorrelation coefficient was defined and employed as the index for real-time stall detection. In addition, to verify the accuracy of detection results, the tested signals were also analyzed off-line by wavelet transform to detect the actual starting point of rotating stall. The comparison results show that the stall detection method based on the symmetrized dot pattern (SDP) analysis can accurately detect the starting point of rotating stall in centrifugal fans within a short period of 0.05 s. [ABSTRACT FROM AUTHOR]

We report the enhancement of spin-orbit torques (SOT) in MnAl/Ta films with improving chemical ordering through annealing. The switching current density is increased due to enhanced saturation magnetization MS and effective anisotropy field HK after annealing. Using harmonic measurements, we have found that both dampling-like effective field HD and field-like effective field HF were increased in the temperature range of 50 to 300 K, and the annealing has also enhanced the value of the spin Hall angle. The improved chemical ordering is considered to have enhanced the interfacial spin transparency and the transmitting of the spin current in the MnAl layer. The results suggest that MnAl films with high bulk perpendicular magnetic anisotropy are ideal for a systematic examination of SOT, in which the related magnetic and transport behaviors can be controllably varied with thermally tuned chemical ordering. [ABSTRACT FROM AUTHOR]