1.5 Classification of magnetic materials
The wide variety of magnetic materials can be sharply divided into three groups: Soft magnetic materials (easy to magnetize and demagnetize) Hard magnetic materials (hard to magnetize and demagnetize) Semi-hard magnetic materials
The soft magnetic materials have the characteristic feature of high permeability, and it is chiefly this flux-multiplying power of magnetically soft materials that fits them for their job in machines and devices.
Hard magnetic materials are made into permanent magnets. Here a high coercivity is a primary requirement because a permanent magnet once magnetized, must be able to resist the demagnetizing action of stray fields, including its own.
Semi-hard magnets can be regarded as a special category of permanent magnets which are used for analog and digital magnetic recording.
1.5.1 Soft magnetic materials
Soft
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These alloys are used for applications which require magnets in the form of strips, rods and wires or those required for the production of stamped-bent and machined parts.
Semi hard material includes MAGNETOFLEX, SENSORVAC and SEMIVAC.
MAGNETOFLEX refers to permanent magnetic alloy that is composed of Cobalt, Iron and Vanadium. The typical applications of this form of alloy are motors, compass needles and tachometers.
SENSORVAC and SEMIVAC is cobalt-free alloy composed of Iron and Nickel. They are manufactured in the form of tape and wire and used in Electronic Article Surveillance (EAS) systems.
1.6 Magnetic anisotropy
Magnetic anisotropy is defined as the directional dependence of the magnetic properties for materials. Strong easy-axis anisotropy is a prerequisite for hard magnetism while near-zero anisotropy is desirable for soft magnets. Generally, the tendency for magnetization to lie along an easy axis is represented by the energy density
We use metals to construct all kinds of structures, from bridges to skyscrapers to elevators. The strength as well as durability of materials that are crafted out of metal make the materials ideal not only for construction but also for many other applications.
In the twentieth century the medical field has seen many changes. One way that hospitals and nursing specifically has changed and implemented the changes is by pursuing accreditations, awards, and recognitions. The purpose of this paper is to understand Magnet Status and the change required by hospitals to achieve it.
Throughout the past century, investigations of quantum and particle physics phenomena have proven to show the most significant concepts and ideas in the physical and sub-atomic world. However, the discoveries yet to be made are endless. One of the most fascinating concepts in the sub-atomic universe is the idea of spintronics. Spintronics is the quantum study of the independent angular momentum (not to be confused with the orbital angular momentum of the electron) of a particle, typically that of an electron (Introduction). An electron is a fundamental particle, with a negative charge, and is independently studied in the process of spintronic devices. The spin angular momentum of electrons is ±½ћ. Devices that use the properties
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During the late 1970's, the world of diagnostic imaging changed drastically due to the introduction of Magnetic Resonance Imaging, also known as MRI. For over 30 years, they have grown to become one of the most significant imaging modalities found in the hospitals and clinics ("EDUCATIONAL OBJECTIVES AND FACULTY INFORMATION"). During its ancient days, these machines were referred to as NMRI machines or, “Nuclear Magnetic Resonance Imaging.” The term “nuclear” comes from the fact that the machine has the capability of imaging an atom's nucleus. Eventually, the term was dropped and replaced with just MRI, because “nuclear” did not sit well with the public view ("EDUCATIONAL OBJECTIVES AND FACULTY INFORMATION"). Many people interpreted the machine to produce an excess amount of radiation in comparison to the traditional X-ray machine. What many of them were unaware of, MRI does not disperse a single ounce of ionizing radiation making it one of the safest diagnostic imaging machine available to this date. MRI machines actually use strong magnetic fields and radio waves to produce high quality images consisting of precise details that cannot be seen on CT (Computed Tomography) or X-ray. The MRI magnet is capable of fabricating large and stable magnetic fields making it the most important and biggest component of MRI. The magnet in an MRI machine is measured on a unit called Tesla. While regular magnets commonly use a unit called gauss (1 Tesla = 10,000 gauss). Compared to Earth's magnetic field (0.5 gauss), the magnet in MRI is about 0.5 to 3.0 tesla range meaning it is immensely strong. The powerful magnetic fields of the machine has the ability to pull on any iron-containing objects and may cause them to abruptly move with great for...
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