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The manipulation of spin–orbit torque (SOT) manifests enormous potentiality in the field of spintronics due to virtues of low power consumption, ultrafast spin-flips, and high-density integration. Increaser the spin hall angle of the spin source layer or the SOT efficiency are the key approaches of achieving low power spintronics. Here, we report an enhancement of spin–orbit torques in Ta/Co/Pt heterostructures using low-voltage ionic liquid gating. The effective spin Hall angle increased threefold with an applied voltage of 2 V. As expected, the enhanced spin Hall angle lowers the critical current density by 66.7% (1.14 × 107 to 3.80 × 106 A cm−2). By the lock-in harmonic Hall voltage measurements, the outstanding performance of manipulation of the spin–orbit coupling originates from the electrostatic doping interracially by the ionic liquid. In addition to the significant fundamentals, our work could be feasibly wielded toward the spintronics such as memory and logic devices in the behaviors of energy-efficient and impressive tunability. [ABSTRACT FROM AUTHOR]

This study was a retrospective study to investigate factors related to difficult tracheostomy decannulation, and to evaluate outcomes of tracheostomized neurosurgical patients. All consecutive tracheostomized neurosurgical patients in the Prince of Wales Hospital between 1st September 2016 and 31st August 2019 were reviewed retrospectively. Patients were grouped into easy decannulation and difficult decannulation groups using 3 months as cut-off time. Risk factors were analysed and outcomes were compared. One hundred thirty-one patients were included. In univariate analyses, male gender, GCS less than or equal to 8 on admission, the presence of vocal cord palsy at 3 months, and pneumonia within 1-month post-tracheostomy were associated with difficult decannulation. In multivariable logistic regression for difficult decannulation, GCS on admission, the presence of vocal cord palsy at 3 months, and the presence of pneumonia within 1-month post-tracheostomy remained statistically significant. The easy decannulation group had a shorter length of in-patient stay, higher survival rate, and more favourable neurological outcome (GOS 4–5) than the difficult decannulation group at both 6 months and 1 year. The majority of easy decannulation group patients (54%) were discharged to home, while the majority of the difficult decannulation group (42%) of patients were discharged to the infirmary. GCS less than or equal to 8 on admission, the presence of vocal cord palsy, and the presence of pneumonia were associated with difficult tracheostomy decannulation in neurosurgical patients. Difficult decannulation is associated with a longer length of in-patient stay and poor neurological outcomes. [ABSTRACT FROM AUTHOR]

Background The diagnostic accuracy of frameless stereotactic brain biopsy has been reported, but there is limited literature focusing on the reasons for nondiagnostic cases. In this study, we evaluate the diagnostic accuracy of frameless stereotactic brain biopsy, compare it with the current international standard, and review the field for improvement. Methods This is a retrospective analysis of consecutive, prospectively collected frameless stereotactic brain biopsies from 2007 to 2020. We evaluated the diagnostic accuracy of the frameless stereotactic brain biopsies using defined criteria. The biopsy result was classified as conclusive, inconclusive, or negative, based on the pathologic, radiologic, and clinical diagnosis concordance. For inconclusive or negative results, we further evaluated the preoperative planning and postoperative imaging to review the errors. A literature review for the diagnostic accuracy of frameless stereotactic biopsy was performed for the validity of our results. Results There were 106 patients with 109 biopsies performed from 2007 to 2020. The conclusive diagnosis was reached in 103 (94.5%) procedures. An inconclusive diagnosis was noted in four (3.7%) procedures and the biopsy was negative in two (1.9%) procedures. Symptomatic hemorrhage occurred in one patient (0.9%). There was no mortality in our series. Registration error (RE) and inaccurate targeting occurred in three trigonal lesions (2.8%), sampling of the nonrepresentative part of the lesion occurred in two cases (1.8%), and one biopsy (0.9%) for lymphoma was negative due to steroid treatment. The literature review suggested that our diagnostic accuracy was comparable with the published literature. Conclusion The frameless stereotactic biopsy is a safe procedure with high diagnostic accuracy only if meticulous preoperative planning and careful intraoperative registration is performed. The common pitfalls precluding a conclusive diagnosis are RE and biopsies at nonrepresentative sites. [ABSTRACT FROM AUTHOR]

The flexible electronics have application prospects in many fields, including as wearable devices and in structural detection. Spintronics possess the merits of a fast response and high integration density, opening up possibilities for various applications. However, the integration of miniaturization on flexible substrates is impeded inevitably due to the high Joule heat from high current density (1012 A/m2). In this study, a prototype flexible spintronic with device antiferromagnetic/ferromagnetic heterojunctions is proposed. The interlayer coupling strength can be obviously altered by sunlight soaking via direct photo-induced electron doping. With the assistance of a small magnetic field (±125 Oe), the almost 180° flip of magnetization is realized. Furthermore, the magnetoresistance changes (15~29%) of flexible spintronics on fingers receiving light illumination are achieved successfully, exhibiting the wearable application potential. Our findings develop flexible spintronic sensors, expanding the vision for the novel generation of photovoltaic/spintronic devices. [ABSTRACT FROM AUTHOR]

Measurement of 3D vector magnetic field is of vital importance for the development of magnetic navigation, biomedical diagnosis, and microimaging. Traditional 3D magnetic sensors require cooperation of multiple sensors on three orthogonal planes, resulting in disadvantages of bulky size and low spatial resolution. Recently proposed spin orbit torque sensor based on ferromagnetic/heavy‐metal heterostructures can detect three magnetic field components individually due to the different symmetries of current‐polarity‐dependent magnetization dynamic. However, the large driving current density and complex driving procedure hinder their practical application, especially in AC magnetic field detection. Herein, 3D magnetic sensors with dramatically reduced driving current density are reported, one fifth of the original value, by exquisite engineering of the magnetic anisotropy in Pt/Co/Ta heterostructures. With further reduced perpendicular magnetic anisotropy, the sensor in the easy‐cone state demonstrates a record‐high sensitivity of 31196 V A−1 T−1. More importantly, the easy‐cone state sensor can work with an ultralow driving current density of 3.8 kA cm−2, which is three orders lower than previous results. Although easy‐cone state sensor can only measure the z‐axis field, highly compact 3D magnetic sensor can be realized by adoption of two anisotropic magnetoresistance sensors, promising great potential application in space‐ and energy‐restricted scenarios. [ABSTRACT FROM AUTHOR]

Ferromagnetic insulator thin film nanostructures are becoming the key component of the state‐of‐the‐art spintronic devices, for instance, yttrium iron garnet (YIG) with low damping, high Curie temperature, and high resistivity is explored into many spin–orbit interactions related spintronic devices. Voltage modulation of YIG, with great practical/theoretical significance, thus can be widely applied in various YIG‐based spintronics effects. Nevertheless, to manipulate ferromagnetism of YIG through electric field (E‐field), instead of current, in an energy efficient manner is essentially challenging. Here, a YIG/Cu/Pt layered nanostructure with a weak spin–orbit coupling interaction is fabricated, and then the interfacial magnetism of the Cu and YIG is modified via ionic liquid gating method significantly. A record‐high E‐field‐induced ferromagnetic resonance field shift of 1400 Oe is achieved in YIG (17 nm)/Cu (5 nm)/Pt (3 nm)/ionic liquid/Au capacitor layered nanostructures with a small voltage bias of 4.5 V. The giant magnetoelectric tunability comes from voltage‐induced extra ferromagnetic ordering in Cu layer, confirmed by the first‐principle calculation. This E‐field modulation of interfacial magnetism between light metal and magnetic isolator may open a door toward compact, high‐performance, and energy‐efficient spintronic devices. A record‐high E‐field‐induced ferromagnetic resonance field shift of 1400 Oe is achieved in an yttrium iron garnet/Cu/Pt/ionic liquid/Au capacitor heterostructure with a small voltage bias of 4.5 V characterized via in situ electron spin resonance spectroscopy. The giant magnetoelectric tunability comes from voltage‐induced extra ferromagnetic ordering in the Cu layer, confirmed by the first‐principle calculation. [ABSTRACT FROM AUTHOR]