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Bit-patterned Recording
Patterned media (also known as bit-patterned media or BPM) is a potential future hard disk drive technology to record data in magnetic islands (one bit per island), as opposed to current hard disk drive technology where each bit is stored in within a continuous magnetic film. The islands would be patterned from a precursor magnetic film using nanolithography. It is one of the proposed technologies to succeed perpendicular recording due to the greater storage densities it would enable. BPM was introduced by Toshiba in 2010. Comparison with existing HDD technology In existing hard disk drives, data is stored in a thin magnetic film. This film is deposited so that it consists of isolated (weakly exchange coupled) grains of material of around diameter. One bit of data consists of around that are magnetized in the same direction (either "up" or "down", with respect to the plane of the disk). One method of increasing storage density has been to reduce the average grain volume. Howev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hard Disk Drive
A hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage with one or more rigid rapidly rotating platters coated with magnetic material. The platters are paired with magnetic heads, usually arranged on a moving actuator arm, which read and write data to the platter surfaces. Data is accessed in a random-access manner, meaning that individual blocks of data can be stored and retrieved in any order. HDDs are a type of non-volatile storage, retaining stored data when powered off. Modern HDDs are typically in the form of a small rectangular box. Introduced by IBM in 1956, HDDs were the dominant secondary storage device for general-purpose computers beginning in the early 1960s. HDDs maintained this position into the modern era of servers and personal computers, though personal computing devices produced in large volume, like cell phones and tablets, rely on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanolithography
Nanolithography (NL) is a growing field of techniques within nanotechnology dealing with the engineering (patterning e.g. etching, depositing, writing, printing etc) of nanometer-scale structures on various materials. The modern term reflects on a design of structures built in range of 10−9 to 10−6 meters, i.e. nanometer scale. Essentially, the field is a derivative of lithography, only covering very small structures. All NL methods can be categorized into four groups: photo lithography, scanning lithography, soft lithography and other miscellaneous techniques. History The NL has evolved from the need to increase the number of sub-micrometer features (e.g. transistors, capacitors etc.) in an integrated circuit in order to keep up with Moore's Law. While lithographic techniques have been around since the late 18th century, none were applied to nanoscale structures until the mid-1950s. With evolution of the semiconductor industry, demand for techniques capable of producing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perpendicular Recording
Perpendicular recording (or perpendicular magnetic recording, PMR), also known as conventional magnetic recording (CMR), is a technology for data recording on magnetic media, particularly hard disks. It was first proven advantageous in 1976 by Shun-ichi Iwasaki, then professor of the Tohoku University in Japan, and first commercially implemented in 2005. The first industry-standard demonstration showing unprecedented advantage of PMR over longitudinal magnetic recording (LMR) at nanoscale dimensions was made in 1998 at IBM Almaden Research Center in collaboration with researchers oData Storage Systems Center(DSSC) – a National Science Foundation (NSF) Engineering Research Center (ERCs) at Carnegie Mellon University (CMU). Advantages Perpendicular recording can deliver more than three times the storage density of traditional longitudinal recording. In 1986, Maxell announced a floppy disk using perpendicular recording that could store . Perpendicular recording was later used b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toshiba
, commonly known as Toshiba and stylized as TOSHIBA, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan. Its diversified products and services include power, industrial and social infrastructure systems, elevators and escalators, electronic components, semiconductors, hard disk drives (HDD), printers, batteries, lighting, as well as IT solutions such as quantum cryptography which has been in development at Cambridge Research Laboratory, Toshiba Europe, located in the United Kingdom, now being commercialised. It was one of the biggest manufacturers of personal computers, consumer electronics, home appliances, and medical equipment. As a semiconductor company and the inventor of flash memory, Toshiba had been one of the top 10 in the chip industry until its flash memory unit was spun off as Toshiba Memory, later Kioxia, in the late 2010s. The Toshiba name is derived from its former name, Tokyo Shibaura Denki K.K. (Tokyo Shibaura Elect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exchange Interaction
In chemistry and physics, the exchange interaction (with an exchange energy and exchange term) is a quantum mechanical effect that only occurs between identical particles. Despite sometimes being called an exchange force in an analogy to classical force, it is not a true force as it lacks a force carrier. The effect is due to the wave function of indistinguishable particles being subject to exchange symmetry, that is, either remaining unchanged (symmetric) or changing sign (antisymmetric) when two particles are exchanged. Both bosons and fermions can experience the exchange interaction. For fermions, this interaction is sometimes called Pauli repulsion and is related to the Pauli exclusion principle. For bosons, the exchange interaction takes the form of an effective attraction that causes identical particles to be found closer together, as in Bose–Einstein condensation. The exchange interaction alters the expectation value of the distance when the wave functions of two or more ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Activation Energy
In chemistry and physics, activation energy is the minimum amount of energy that must be provided for compounds to result in a chemical reaction. The activation energy (''E''a) of a reaction is measured in joules per mole (J/mol), kilojoules per mole (kJ/mol) or kilocalories per mole (kcal/mol). Activation energy can be thought of as the magnitude of the potential barrier (sometimes called the energy barrier) separating minima of the potential energy surface pertaining to the initial and final thermodynamic state. For a chemical reaction to proceed at a reasonable rate, the temperature of the system should be high enough such that there exists an appreciable number of molecules with translational energy equal to or greater than the activation energy. The term "activation energy" was introduced in 1889 by the Swedish scientist Svante Arrhenius. Other uses Although less commonly used, activation energy also applies to nuclear reactions and various other physical phenomena. Te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superparamagnetism
Superparamagnetism is a form of magnetism which appears in small ferromagnetic or ferrimagnetic nanoparticles. In sufficiently small nanoparticles, magnetization can randomly flip direction under the influence of temperature. The typical time between two flips is called the Néel relaxation time. In the absence of an external magnetic field, when the time used to measure the magnetization of the nanoparticles is much longer than the Néel relaxation time, their magnetization appears to be in average zero; they are said to be in the superparamagnetic state. In this state, an external magnetic field is able to magnetize the nanoparticles, similarly to a paramagnet. However, their magnetic susceptibility is much larger than that of paramagnets. The Néel relaxation in the absence of magnetic field Normally, any ferromagnetic or ferrimagnetic material undergoes a transition to a paramagnetic state above its Curie temperature. Superparamagnetism is different from this standard transi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ion Beam Lithography
Ion-beam lithography is the practice of scanning a focused beam of ions in a patterned fashion across a surface in order to create very small structures such as integrated circuits or other nanostructures. Details Ion-beam lithography has been found to be useful for transferring high-fidelity patterns on three-dimensional surfaces. Ion-beam lithography offers higher resolution patterning than UV, X-ray, or electron beam lithography because these heavier particles have more momentum. This gives the ion beam a smaller wavelength than even an e-beam and therefore almost no diffraction. The momentum also reduces scattering in the target and in any residual gas. There is also a reduced potential radiation effect to sensitive underlying structures compared to x-ray and e-beam lithography. Ion-beam lithography, or ion-projection lithography, is similar to Electron beam lithography, but uses much heavier charged particles, ions. In addition to diffraction being negligible, ions move ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron Beam Lithography
Electron-beam lithography (often abbreviated as e-beam lithography, EBL) is the practice of scanning a focused beam of electrons to draw custom shapes on a surface covered with an electron-sensitive film called a resist (exposing). The electron beam changes the solubility of the resist, enabling selective removal of either the exposed or non-exposed regions of the resist by immersing it in a solvent (developing). The purpose, as with photolithography, is to create very small structures in the resist that can subsequently be transferred to the substrate material, often by etching. The primary advantage of electron-beam lithography is that it can draw custom patterns (direct-write) with sub-10 nm resolution. This form of maskless lithography has high resolution and low throughput, limiting its usage to photomask fabrication, low-volume production of semiconductor devices, and research and development. Systems Electron-beam lithography systems used in commercial applications ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasma Etching
Plasma etching is a form of plasma processing used to fabricate integrated circuits. It involves a high-speed stream of glow discharge (plasma) of an appropriate gas mixture being shot (in pulses) at a sample. The plasma source, known as etch species, can be either charged (ions) or neutral (atoms and radicals). During the process, the plasma generates volatile etch products at room temperature from the chemical reactions between the elements of the material etched and the reactive species generated by the plasma. Eventually the atoms of the shot element embed themselves at or just below the surface of the target, thus modifying the physical properties of the target. Mechanisms Plasma generation A plasma is a high energetic condition in which a lot of processes can occur. These processes happen because of electrons and atoms. To form the plasma electrons have to be accelerated to gain energy. Highly energetic electrons transfer the energy to atoms by collisions. Three different pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copolymer
In polymer chemistry, a copolymer is a polymer derived from more than one species of monomer. The polymerization of monomers into copolymers is called copolymerization. Copolymers obtained from the copolymerization of two monomer species are sometimes called ''bipolymers''. Those obtained from three and four monomers are called ''terpolymers'' and ''quaterpolymers'', respectively. Copolymers can be characterized by a variety of techniques such as NMR spectroscopy and size-exclusion chromatography to determine the molecular size, weight, properties, and composition of the material. Commercial copolymers include acrylonitrile butadiene styrene (ABS), styrene/butadiene co-polymer (SBR), nitrile rubber, styrene-acrylonitrile, styrene-isoprene-styrene (SIS) and ethylene-vinyl acetate, all of which are formed by chain-growth polymerization. Another production mechanism is step-growth polymerization, which is used to produce the nylon-12/6/66 copolymer of nylon 12, nylon 6 and nylon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heat-assisted Magnetic Recording
Heat-assisted magnetic recording (HAMR) (pronounced "''hammer")'' is a magnetic storage technology for greatly increasing the amount of data that can be stored on a magnetic device such as a hard disk drive by temporarily heating the disk material during writing, which makes it much more receptive to magnetic effects and allows writing to much smaller regions (and much higher levels of data on a disk). The technology was initially seen as extremely difficult to achieve, with doubts expressed about its feasibility in 2013. The regions being written must be heated in a tiny area - small enough that diffraction prevents the use of normal laser focused heating - and requires a heating, writing and cooling cycle of less than 1 nanosecond, while also controlling the effects of repeated spot-heating on the drive platters, the drive-to-head contact, and the adjacent magnetic data which must not be affected. These challenges required the development of nano-scale surface plasmons (surfa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
