Field-Free Spin-Orbit Torque Driven Switching of Perpendicular Magnetic Tunnel Junction through Bending Current.

Current-induced spin-orbit torques (SOTs) enable fast and efficient manipulation of the magnetic state of magnetic tunnel junctions (MTJs), making them attractive for memory, in-memory computing, and logic applications. However, the requirement of the external magnetic field to achieve deterministic switching in perpendicularly magnetized SOT-MTJs limits its implementation for practical applications. Here, we introduce a field-free switching (FFS) solution for the SOT-MTJ device by shaping the SOT channel to create a "bend" in the SOT current. The resulting bend in the charge current creates a spatially nonuniform spin current, which translates into inhomogeneous SOT on an adjacent magnetic free layer enabling deterministic switching. We demonstrate FFS experimentally on scaled SOT-MTJs at nanosecond time scales. This proposed scheme is scalable, material-agnostic, and readily compatible with wafer-scale manufacturing, thus creating a pathway for developing purely current-driven SOT systems.

Effectiveness of SNAPPS for improving clinical reasoning in postgraduates: randomized controlled trial.

BACKGROUND: In-patient postgraduate teaching suffers with issues like long and unstructured presentations inclusive of a lot of historical information and time constraints due to increasing workload. A six-step pneumonic SNAPPS a learner-centered model modifies the learning encounter by condensing the reporting of facts while encouraging clinical reasoning. This study was planned with the aim to evaluate the effectiveness of SNAPPS as compared to traditional case presentation for facilitating clinical reasoning in inpatient setting. We also wanted to understand perceptions of postgraduates and teachers about this new method of case presentation. METHODS: This open labeled randomized controlled trial was carried amongst the 18 residents of department of Medicine, MGIMS. The teachers and residents in the SNAPPS were sensitized to SNAPPS technique by using videos, role plays and handouts over 2 sessions of 30 min each. Twenty-seven case presentations (3/resident) were carried out in each group (total 54 case presentations). Data was recorded into validated data recording sheet after each presentation and feedback was taken from the teacher as well as residents regarding their perception. RESULTS: The SNAPPS model heralds a change in the preceptor training, pairing faulty development and learner development as companions in education. Guided by the SNAPPS technique, students summarized patient findings concisely (7 vs. 2.7 vs. 5.22vs. 2.33, p = 0.0057) while maintaining the same degree of thoroughness as in traditional case presentations. The students in the SNAPPS group were clearer about their diagnostic hypothesis and compared and contrasted their different diagnosis well (2.56 vs. 1.74, p value =0.002). The students in the SNAPPS group initiated patient management discussion almost 20% more times as compared to the control group. CONCLUSION: We conclude that SNAPPS a learner centered technique for case presentations facilitated the expression of clinical diagnostic reasoning and case based uncertainties in the inpatient setting without extending the unusual length of the student case presentations. It also paved way for enhanced self-directed learning.

A quantum sensing metrology for magnetic memories.

Magnetic random access memory (MRAM) is a leading emergent memory technology that is poised to replace current non-volatile memory technologies such as eFlash. However, controlling and improving distributions of device properties becomes a key enabler of new applications at this stage of technology development. Here, we introduce a non-contact metrology technique deploying scanning NV magnetometry (SNVM) to investigate MRAM performance at the individual bit level. We demonstrate magnetic reversal characterization in individual, <60 nm-sized bits, to extract key magnetic properties, thermal stability, and switching statistics, and thereby gauge bit-to-bit uniformity. We showcase the performance of our method by benchmarking two distinct bit etching processes immediately after pattern formation. In contrast to ensemble averaging methods such as perpendicular magneto-optical Kerr effect, we show that it is possible to identify out of distribution (tail-bits) bits that seem associated to the edges of the array, enabling failure analysis of tail bits. Our findings highlight the potential of nanoscale quantum sensing of MRAM devices for early-stage screening in the processing line, paving the way for future incorporation of this nanoscale characterization tool in the semiconductor industry.

Time-resolved imaging of pulse-induced magnetization reversal with a microwave assist field.

The reversal of the magnetization under the influence of a field pulse has been previously predicted to be an incoherent process with several competing phenomena such as domain wall relaxation, spin wave-mediated instability regions, and vortex-core mediated reversal dynamics. However, there has been no study on the direct observation of the switching process with the aid of a microwave signal input. We report a time-resolved imaging study of magnetization reversal in patterned magnetic structures under the influence of a field pulse with microwave assistance. The microwave frequency is varied to demonstrate the effect of resonant microwave-assisted switching. We observe that the switching process is dominated by spin wave dynamics generated as a result of magnetic instabilities in the structures, and identify the frequencies that are most dominant in magnetization reversal.

Acute pancreatitis complicating severe dengue.

Dengue is an arthropod borne viral infection endemic in tropical and subtropical continent. Severe dengue is life threatening. Various atypical presentations of dengue have been documented. But we present a rare and fatal complication of severe dengue in form of acute pancreatitis. A 27-year-old male had presented with severe dengue in decompensated shock and with pain in abdomen due to pancreatitis. The pathogenesis of acute pancreatitis in dengue is not clearly understood, but various mechanisms are postulated. The awareness and timely recognition of this complication is very important for proper management.

Delayed presentation of port-site metastasis from an unknown gastrointestinal malignancy following laparoscopic cholecystectomy.

Port-site metastasis (PSM) is often encountered during laparoscopic surgery in patients with malignancy. We report a 45-year-old woman who presented with a single PSM from papillary adenocarcinoma after undergoing laparoscopic cholecystectomy for calculus cholecystitis. Post cholecystectomy, a diagnosis of chronic cholecystitis was confirmed on histopathology. The patient presented with a mass at the site of epigastric port 28 months after surgery. PSM was suspected on clinical examination, which was supported by findings on computed tomography and further confirmed by fine-needle aspiration cytology of the lump. The patient underwent surgical clearance of the mass, and histopathological examination proved the lesion to be papillary adenocarcinoma. The site of the primary tumour was not detected even after thorough examination. Based on the histopathology report following local surgical clearance, the patient was started on chemotherapy. This case is unusual because of the long delay prior to the presentation of PSM and the unknown primary malignancy.