Dynamics of perpendicular recording heads

3D modeling and inductance measurements were used to design an ultra-high frequency perpendicular system. Kerr microscopy and spin-stand experiments with focused ion beam (FI-B) trimmed perpendicular heads and perpendicular media directly verified the high frequency concepts

Magnetic characterization of perpendicular recording media

In this paper, we describe techniques for the magnetic characterization of perpendicular recording media. Such measurements made using traditional techniques, such as the vibrating sample magnetometry (VSM) and alternating gradient force magnetometer (AGFM), have to be corrected for the sample shape demagnetizing factor, which is often found not to be equal to -4p. For measurements other than the simple hysteresis loop, such as remanence curves, this correction must be carried out in real time and we describe the method by which this can be achieved and the process for achieving the correct demagnetization of perpendicular films prior to measurements of the isothermal remanent magnetization curve. A further complication is that real perpendicular media have a soft underlayer beneath the recording layer, which swamps and confuses signals from instruments such as VSM or AGFM. Hence, we describe the construction and use of a magnetooptical Kerr effect magnetometer, which does not penetrate significantly into the soft layer and enables the perpendicular layer to be measured independently. We describe the properties of a traditional alloy perpendicular medium and a Co-Pd multilayer system, which in the latter case exhibits multiple switching behavior. We also address the issue of the effect of the soft underlayer on the coupling in similar longitudinal films and find that the presence of the underlayer induces significant additional coupling effects that may well give rise to an increase in noise in recorded signal

Probing punctual magnetic singularities during magnetization process in FePd films

We report the use of Lorentz microscopy to observe the domain wall structure during the magnetization process in FePd thin foils. We have focused on the magnetic structure of domain walls of bubble-shaped magnetic domains near saturation. Regions are found along the domain walls where the magnetization abruptly reverses. Multiscale magnetic simulations shown that these regions are vertical Bloch lines (VBL) and the different bubble shapes observed are then related to the inner structure of the VBLs. We were thus able to probe the presence of magnetic singularities as small as Bloch points in the inner magnetization of the domain walls

Disorder Effect on the Vortex Pinning by the Cooling Process Control in the Organic Superconductor κ\kappa-(BEDT-TTF)2_2Cu[N(CN)2_2]Br

We investigate the influence of disorders in terminal ethylene groups of BEDT-TTF molecules (ethylene-disorders) on the vortex pinning of the organic superconductor $\kappa$-(BEDT-TTF)$_2$Cu[N(CN)$_2$]Br. Magnetization measurements are performed under different cooling-processes. The second peak in the magnetization hysteresis curve is observed for all samples studied, and the hysteresis width of the magnetization becomes narrower by cooling faster. In contradiction to the simple pinning effect of disorder, this result shows the suppression of the vortex pinning force by introducing more ethylene-disorders. The ethylene-disorder domain model is proposed for explaining the observed result. In the case of the system containing a moderate number of the ethylene-disorders, the disordered molecules form a domain structure and it works as an effective pinning site. On the contrary, an excess number of the ethylene-disorders may weaken the effect of the domain structure, which results in the less effective pinning force on the vortices.Comment: 6 pages, 6 figure

Image-guided Placement of Magnetic Neuroparticles as a Potential High-Resolution Brain-Machine Interface

We are developing methods of noninvasively delivering magnetic neuroparticles™ via intranasal administration followed by image-guided magnetic propulsion to selected locations in the brain. Once placed, the particles can activate neurons via vibrational motion or magnetoelectric stimulation. Similar particles might be used to read out neuronal electrical pulses via spintronic or liquid-crystal magnetic interactions, for fast bidirectional brain-machine interface. We have shown that particles containing liquid crystals can be read out with magnetic resonance imaging (MRI) using embedded magnetic nanoparticles and that the signal is visible even for voltages comparable to physiological characteristics. Such particles can be moved within the brain (e.g., across midline) without causing changes to neurological firing

Исследование качества жизни родственных доноров фрагмента печени в отдаленном послеоперационном периоде

Introduction. Quality of life (QoL) is a new promising area of clinical medicine that provides the opportunity to assess the state of health of the patient and to have a notion of the surgery effects based on the parameters which are lying at the intersection of scientific approach of the surgeons and subjective point of view of the patient.Materials and methods. The study included 52 living-related liver fragment donors operated between 2009 and 2014. Donors were surveyed after 2–5 years from the surgery. Comparison group was formed by healthy volunteers, students of the Medical University. The Russian version of the non-specific SF-36 questionnaire was used to assess QoL.Results. Donors in the postoperative period have demonstrated a high level of physical parameter (57.65 ± 3.8). Parameter of psychological health in the postoperative period was (52.01 ± 5.2). These figures are comparable with the results in the comparison group (p > 0.05). All donors have returned to normal life.Conclusions. Overall results of this study were similar to those of the foreign colleagues which confirm the high safety of liver resection surgery and the efficacy of SF-36 questionnaire in the assessment of quality of life of the living-related liver fragment donors.Введение. Оценка качества жизни (КЖ) – новое перспективное направление клинической медицины, предоставляющее возможность оценить состояние здоровья пациента и составить представление о последствиях оперативного вмешательства по параметрам, которые находятся на стыке научного подхода хирургов и субъективной точки зрения пациента.Материалы и методы. В исследование были включены 52 родственных донора фрагмента печени, оперированных в период с 2009-го по 2014 год. Доноры опрашивались спустя 2–5 лет после оперативного вмешательства. В качестве группы сравнения выступили здоровые добровольцы – студенты медицинского университета. Для оценки качества жизни применялась русскоязычная версия неспецифического опросника SF-36.Результаты. Доноры в послеоперационном периоде продемонстрировали высокий уровень физического параметра (57,65 ± 3,8). Психологический параметр здоровья в послеоперационном периоде составил 52,01 ± 5,2. Данные показатели сопоставимы с результатами в группе сравнения (р > 0,05). Все доноры вернулись к нормальной жизнедеятельности.Выводы. Результаты настоящего исследования схожи с данными зарубежных коллег, что подтверждает безопасность операции эксплантации фрагментов печени и эффективность опросника SF-36 в оценке качества жизни родственных доноров фрагмента печени