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A novel synchronous permanent magnet planar motor (SPMPM) which with concentric structure winding is investigated in this paper. Topology of this SPMPM is introduced, and as the mover can move freely on the stator, the planar motor is suitable for long-stroke applications in the lithography. Flux density, electromagnetic thrust and back-EMF of the SPMPM are obtained analytically and compared with...
Currently, there is significant attention being paid to the development of high-speed machines including motors and generators. In particular, permanent magnet machines are gaining more traction due to their outstanding efficiency, high power density, small size, low weight, simple mechanical construction, easy maintenance and good reliability. The higher the motor speed, the smaller the electric...
In this paper, a new topological design of permanent magnet (PM) motor with Halbach magnet is introduced and investigated. To better evaluate the performance of different types of motors, a novel approach for the design optimization based on an improved Tabu search algorithm and finite element method (FEM) is proposed. The improvements include a normalized step vector for different search spaces,...
In recent years, there are lots of heart diseases and some of these, e.g. congestive heart failure, can not only make heartbeat slowly, but also can cause the heart to pump blood powerlessly. In order to solve the problems, ventricular assist devices (VADs) had been proposed [1, 2]. They could help hearts to pump blood powerfully around human body, and mitigate uncomfortableness of hearts. Currently,...
Owing to their giant value of magnetic moment under specific conditions, certain phases of iron nitride have received considerable attention of the scientific community worldwide. In particular, α”-Fe16N2 and γ'-Fe4N phases have been studied extensively due to their excellent ferromagnetic characteristics.
During the last years, anisotropic NdFeB films with good performance have been extensively investigated and widely used in application where high BHmax are required, such as microelectromechanical system(MEMS), magnetic recording media and millisize motors or actuators. So, many groups have tried to prepare NdFeB films by sputtering deposition[1]. But the permanent magnet performance of films always...
Hard disk drives (HDDs) are among the most widely used information storage components in these digital times, since they were commercialized in late 1970s. The perpendicular magnetic recording (PMR) media using (CoCrPt)x(Metal Oxide)1−x magnetic alloys have reached an areal density of 700GB/in2 and beyond[1]. The current researches focus on achieving higher grain refinement and increasing uniaxial...
Heat-assisted magnetic recording (HAMR) is a promising approach for enabling large increases in the storage density. In HAMR systems, the high temperature working condition brings challenges for head-media interface, where lubricant depletion and carbon graphitization may occur and cause failure. To explore the effect of laser heating on the change of lubricant and carbon overcoat layers, HAMR FID...
When the storage density is coming into several Tb/in2, the head-disk spacing will drop into angstrom-scale regime [1]. At such small clearance, the electrostatic and intermolecular forces have become increasingly significant. It was reported that the electrostatic force produced by electronic potential difference between head and disk can be larger than the van der Waals force even if the slider...
Heat assisted magnetic recording (HAMR) can overcome the super-paramagnetic limit and increase areal density beyond 1 Tb/in2 in hard disk drives [1]. In HAMR, a pulsed laser beam is first used to heat the magnetic medium beyond its Curie temperature and then data is magnetically recorded during the cool-down process while the coercivity of the medium is still low. High temperatures at the head disk...
In hard disk drives (HDDs), the head-disk spacing needs to be reduced to less than 2 nm to achieve a target recording density of 4 Tbit/in2 [1]. At such a small spacing, liquid perfluoropolyether (PFPE) lubricant films coated on disk surfaces are more frequently subjected to shear confined between the head and the disk. Therefore, a detailed understanding of the shear phenomenon is essential for improving...
With the implementation of the thermal flying height control (TFC) slider, the flying height is reduced to approximately 2 nanometers [1], the gaseous rarefaction effects, surface roughness and surface accommodation effects must be taken into account. The surface accommodation coefficient (AC) is an important factor to govern the flying characteristics of the air bearing slider [2-3]. Effects of gaseous...
The eddy-current exists in silicon steel sheets when the laminated core works under the sinusoidal or rotational excitation. The nonlinear electromagnetic field in the magnetic core will be influenced by the eddy-current. Especially, when the power transformer operates in dc bias condition, the DC flux may saturate the ferromagnetic core rapidly and significantly, leading to increased iron loss and...
In 2006, the MIT (Massachusetts Institute of Technology) research team reports their experiment on lighting up a 60-W bulb with two 60-cm diameter coils which are separated by a distance of 2 m [1]. The wireless power transfer technology has, since then, received a surge of interests from all over the world and has now been applied to many areas such as household appliances, RFID (radio frequency...
The oxide-based diluted magnetic semiconductors (DMSs) with Curie temperatures, Tc, at or above room temperature (RT) have attracted great interest due to their potential applications in spintronic devices.1 Among them, the Fe-doped In2O3 DMS has attracted considerable interest because of the high solubility of Fe in the In2O3 matrix, excellent electrical conductivity, and high optical trans-parency...
Motivated by the experimental isolation of graphene [1], intense investigations have been paid the physical properties of the two-dimensional (2D) honeycomb lattice. Graphene is regarded as a promising material for spintronic applications due to its weak spin-orbit coupling and long spin lifetimes [2]. Up to now, several groups have studied the spin transport properties in graphene with magnetic and...
The successful injection of spin-polarized current into a semiconductor has been expected for a long time in spintronics.[1] The most promising way to achieve it is the use of spin filter materi-als(SFMs), which are magnetic semiconductors.[2] The diluted magnetic semiconductors (DMSs) such as Ga1-xMnxAs can keep both semiconducting and magnetic behavior. However, this strategy is limited by the low...
High voltage porcelain post insulator is one of the most important facilities in power plant and substation in the procedure of generating and transmitting electric energy which is used to hold up the electric transmission line as support bracket and insulate high voltage, when deteriorated or cracked it will pose a serious threat to the normal operation of power system.
This paper proposes a new permanent-magnet vernier (PMV) in-wheel motor to meet the new demands arising from in-wheel electric vehicles. It can offer the advantages of light weight, compact size and low-speed high-torque operation. The mechanical gear can be removed by introducing flux-modulation poles. By using the time-stepping finite element method, the performance of the proposed machine can be...
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