39 research outputs found
Effect of the underlayer on the elastic parameters of the CoFeB/MgO heterostructures
No full text<p><span>SS gratefully acknowledges the financial support from Adam Mickiewicz University under the framework of the “Initiative of Excellence - Research University” (ID-UB 054/13/SNŚ/0031). BR acknowledges financial support from the NCN SONATA-16 project with grant number 2020/39/D/ST3/02378.</span></p>
Influence of CoFeB layer thickness on elastic parameters in CoFeB/MgO heterostructures
No full text<p>This is the dataset for the paper titled 'Influence of CoFeB layer thickness on elastic parameters in CoFeB/MgO heterostructures", published in Scientific Report.</p><p>SS gratefully acknowledges the financial support from Adam Mickiewicz University under the framework of “Initiative of Excellence—Research University” (ID-UB 054/13/SNŚ/0031). BR acknowledges financial support from the Narodowe Centrum Nauki (NCN) SONATA-16 project with grant number 2020/39/D/ST3/02378. The authors sincerely thank Dr. Katsuya Miura and Dr. Hiromasa Takahashi from Hitachi Ltd., Tokyo, Japan, for providing thin films for the study.</p>
Anisotropy of magnetic damping in Ta/CoFeB/MgO heterostructures
No full textAbstract Magnetic damping controls the performance and operational speed of many spintronics devices. Being a tensor quantity, the damping in magnetic thin films often shows anisotropic behavior with the magnetization orientation. Here, we have studied the anisotropy of damping in Ta/CoFeB/MgO heterostructures, deposited on thermally oxidized Si substrates, as a function of the orientation of magnetization. By performing ferromagnetic resonance (FMR) measurements based on spin pumping and inverse spin Hall effect (ISHE), we extract the damping parameter in those films and find that the anisotropy of damping contains four-fold and two-fold anisotropy terms. We infer that four-fold anisotropy originates from two-magnon scattering (TMS). By studying reference Ta/CoFeB/MgO films, deposited on LiNbO3 substrates, we find that the two-fold anisotropy is correlated with in-plane magnetic anisotropy (IMA) of the films, suggesting its origin as the anisotropy in bulk spin–orbit coupling (SOC) of CoFeB film. We conclude that when IMA is very small, it’s correlation with two-fold anisotropy cannot be experimentally identified. However, as IMA increases, it starts to show a correlation with two-fold anisotropy in damping. These results will be beneficial for designing future spintronics devices
Magnetization Reversal in Chains and Clusters of Exchange-Coupled Nickel Nanoparticles
No full textAn ensemble of single domain magnetic nanoparticles often tends to form chains and clusters of various geometries to reduce the micromagnetic energies. The magnetic behavior is different when the nanoparticles are exchange coupled rather than physically separated and only dipolar coupled. Here, we have studied the quasistatic magnetization reversal mechanisms of chains and clusters of exchange-coupled magnetic nanoparticles by experimental and micromagnetic simulation methods. We have explained the experimental magnetic hysteresis behaviors by using the finite element method (FEM) based micromagnetic simulations. We observe that the magnetization reversals in these samples occur through the formation of various local domain states including vortices and fanning- and curling-like modes, depending upon the cluster geometry. The constituent nanoparticles reverse by the quasi-coherent rotation of magnetization, whereas the incoherence between the nanoparticles in the cluster gives rise to the observed domain structures
The inland navigation analysis system BIVAS: Analysis, validation and recommendations for improvement
No full textCivil Engineering and GeosciencesHydraulic Engineerin
Placental Blood Drainage as a Part of Active Management of Third Stage of Labour After Spontaneous Vaginal Delivery
No full textAuthor post-print availableAIM The third stage of labour commences after the delivery of the foetus and ends with the delivery of the placenta and its membranes. Postpartum haemorrhage is the most common cause of maternal mortality and accounts for about 25 % of maternal deaths in India. OBJECTIVES The present study was designed to evaluate the effectiveness of placental blood drainage after spontaneous vaginal delivery as part of active management of third stage of labour in decreasing the duration, blood loss, and complications of the third stage, against no drainage of placental blood. METHODOLOGY Two hundred pregnant patients with 37 or more weeks of gestation, with single live foetus in cephalic presentation, who underwent a spontaneous vaginal delivery, were included in the study. The patients were prospectively randomized equally into two groups (100 each in the study and control groups). Placental blood was drained in all the patients in the study group, whereas in the control group the cord blood was not drained. Blood lost in the third stage of labour was measured by collecting in a disposable conical measuring bag, and blood from the episiotomy was mopped, and the mops were discarded separately. RESULTS The baseline statistics in both the group were comparable. The duration of third stage of labour was 210.5 s in the study group and 302.5 s in the control group. The 'p' value was statistically significant (p ≤ 0.0001). The mean blood loss in study group was 227.5 ml and was 313.3 ml in the control group (p ≤ 0.0001). The incidence of postpartum haemorrhage was 1 % in study group and 9 % in control group. The mean drop in Hb % level was 0.6 gm/dl in study group and 1.1 gm/dl in control group. These above differences were both statistically significant. CONCLUSION Placental blood drainage as part of active management of third stage of labour was effective in reducing the duration, the blood loss, and also the incidence of PPH. Placental blood drainage is a simple, safe, and non-invasive method of managing the third stage of labour, which can be practiced in both tertiary care centres as well as rural setup in addition to the routine uterotonics
Role of Spin–Orbit Coupling on Ultrafast Spin Dynamics in Nonmagnet/Ferromagnet Heterostructures
No full textSpin–orbit coupling (SOC), the interaction between spin and orbital angular momentum of electrons, is imperative to control magnetic properties of nonmagnet (NM)/ferromagnet (FM) heterostructures and design energy-efficient and faster spin-based devices. Here, femtosecond pulsed laser-induced time-resolved magneto-optical Kerr effect magnetometry is employed to investigate magnetization dynamics in different NM/Co20Fe60B20 heterostructures, where the NM layer varies as Cu, Ta, W, Pt, Ta/Ru/Ta, and Si/SiO2 (no underlayer) that differ in SOC strength. It is observed that there is a systematic variation in ultrafast demagnetization time (τm), fast remagnetization time (τr), and Gilbert damping parameter (α) with the SOC strength of the underlayer and an inverse relationship between α and τm, τr is established due to the dominant contribution of spin current transport in ultrafast demagnetization and fast remagnetization processes. The spin pumping formalism estimates the effective spin-mixing conductance (Geff) for different interfaces, which signifies that the high SOC strength of underlayers results in high Geff indicating more efficient transport of spin current through it. This study suggests that the SOC strength of the NM underlayer plays a significant role in controlling the ultrafast demagnetization process through interfacial spin current transport in a NM/FM heterostructure which can be beneficial for the development of ultrafast spintronics devices
Role of Tranexamic Acid in Reducing Blood Loss in Vaginal Delivery
No full textAuthor pre-print available. Available from PubMed Central.Anti-fibrinolytic agents are used to reduce obstetric blood loss as the fibrinolytic system is known to get activated after placental delivery. To evaluate the efficacy of parenteral tranexamic acid in reducing blood loss during normal labour and to compare it with the amount of blood loss in patients who received placebo in the third stage of labour. Patients with spontaneous labour or planned for induction of labour and fulfilling the inclusion criteria were recruited for the study. In each patient, the pre-delivery pulse rate, blood pressure, Hb gm% and PCV% were noted. Labour was monitored carefully using a partogram. The study group received Inj. Oxytocin and Inj. Tranexamic acid. The control group received Inj. Oxytocin and Placebo injection. Immediately after delivery of the baby, when all the liquor was drained, the patient was placed over a blood drape-a disposable conical, graduated plastic collection bag. The amount of blood collected in the blood drape was measured. Then the patient was given pre-weighed pads, which were weighed 2 h post-partum. The blood loss was measured by measuring the blood collected in the drape and by weighing the swabs before and after delivery. The total number of patients studied was 100-equally distributed in both the groups. The age group of the patients and BMI were comparable. There was a significant increase in the pulse rate and decrease in blood pressure in the control group as compared with the study group. The post-delivery haemoglobin and haematocrit were significantly reduced in the control group as compared to the study group. The mean blood loss at the end of 2 h was 105 ml in the study group and 252 ml in the control group. There was a significant increase in the usage of uterotonics and also in the need for blood transfusion in the control group; 12 % of the patients in the control group had to stay for more than 3 days compared to 2 % in the study group. Tranexamic acid injection, an antifibrinolytic agent when given prophylactically after the delivery of the baby, by intravenous route appears to reduce the blood loss and maternal morbidity during normal labour effectively
