Magnetics Business & Technology - Summer 2012 - (Page 4)

EDITOR’S CHOICE Dexter Introduces a High Accuracy Multipole Strip Magnet for Linear Position Measurement layer magnetic systems like a typical hard drive, where defects could be buried beneath the surface. According to NIST researcher Robert McMichael, when left alone, the material’s magnetization is like the surface of a pond on a windless day. The pond is comprised of smaller magnetic moments that come with the quantum mechanical “spin” of electrons. Tap the surface of the pond with a piece of driftwood, or microwaves in this case, and the surface will begin to ripple with spin waves as the microwave energy jostles the spins, which, in turn, jostle their neighbors. “The trick we play is to tune the microwaves to a frequency just outside the band where the spin waves can propagate, except right under our magnetic probe tip,” said McMichael. “It’s like the pond is frozen except for a little melted spot that we can move around to check magnetic properties at different spots in the sample.” The trapped spin waves are disturbed by defects in the material, and this effect allows the defects to be characterized on 100 nm length scales. Previous work had shown this same effect in magnetic spins that were oriented perpendicular to the magnetic film surface, meaning that the individual spins coupled strongly with their neighbors, which limited the resolution. This work adds the extra feature that the magnetic spins are aligned in plane with one another and are not as tightly coupled. This setup is not only more representative of how many magnetic devices would be structured, but also allows for tighter focusing and better resolution. Dexter Magnetic Technologies, Inc. has released a new line of multipole strip magnets for use with the austriamicrosystems line of high resolution linear Hall encoders. The multipole magnet, manufactured from a flexible ferrite, is produced through a repeatable proprietary method which yields accuracy within 2.0 percent of the pole pair (40 µm for 1.0 mm pole). The cumulative pole accuracy is within 1.0 percent per 10 mm. A benefit of this technology is that Dexter is able to offer multiple customer defined strip configurations including industry standard pole spacing of 1.0 mm, 1.2 mm or 2.0 mm, custom magnet lengths and pressure sensitive adhesive backing, while retaining the high level of accuracy. Memory devices based on magnetism are one of the core technologies of the computing industry, and engineers are working to develop new forms of magnetic memory that are faster, smaller, and more energy efficient than today’s flash and SDRAM memory. They now have a new tool developed by a team from the National Institute of Standards and Technology (NIST), the University of Maryland Nanocenter and the Royal Institute of Technology in Sweden, a method to detect defects in magnetic structures as small as a tenth of a micrometer even if the region in question is buried inside a multilayer electronic device. The technique demonstrated at the NIST Center for Nanoscale Technology (CNST) builds on work by researchers at the Ohio State University. The idea is to Trapped beneath the magnetic tip of a microscale cantilever, spin waves can trap and image oscillating be used to non-destructively measure perturbations of a magnetic the properties of magnetic materials field, “spin waves”, in a thin and search for nanoscale defects, espein multilayer magnetic film. Trapped spin waves cially typical hard drive, wheresystems like a defects provide scientists with a could be buried beneath the surface. powerful new tool to non- Credit: McMichael/NIST destructively measure the properties of magnetic materials and search for nanoscale defects that could or have caused memory failures, especially in multi- Nanoscale Magnetic Media Diagnostics by Rippling Spin Waves Molycorp’s Rare Earth Reserves at Mountain Pass Increase by 36 Percent Molycorp, Inc. has announced that its proven and probable reserves of RE minerals at its Mountain Pass, Calif. facility have increased by 36 percent, according to a new independent estimate. The updated estimate, based on the SEC’s rigorous “Industry Guide 7” definition of proven and probable mineral reserves, expands Molycorp’s reserves to 18.4 million short tons of rare earth ore, at an ore grade of 7.98 percent and a cut-off grade of 5 percent. This compares to a previous 2010 estimate of Molycorp’s proven and probable reserves of 13.6 million short tons. Both independent analyses were done by SRK Consulting of Lakewood, Colo., an industry mining consulting firm that specializes in such estimates. SRK now estimates that the proven and probable component of Molycorp’s ore body contains approximately 2.94 billion pounds (1.3 million metric tons) of contained rare earth oxide (REO) equivalent. This compares to the previous estimate of 2.24 billion pounds of contained REO product (1.02 million metric tons). “The SEC’s Industry Guide 7 standard of measuring proven and probable reserves is the most rigorous standard in the industry, and the Mountain Pass ore body is one of the only rare earth deposits in the world that is measured by such a high standard,” said Mark A. Smith, Molycorp’s president and CEO. “I am pleased to see our world-class deposit continue to grow in size, and I believe that our ongoing exploratory drilling at Mountain Pass may show an even larger estimate of proven and probable reserves once that work is completed.” www.MagneticsMagazine.com 4 Magnetics Business & Technology • Summer 2012 http://www.MagneticsMagazine.com

Table of Contents for the Digital Edition of Magnetics Business & Technology - Summer 2012

Magnetics Business & Technology - Summer 2012
Editor's Choice
Injection Molded Magnets for Electrical Machines
The Process of Developing and Testing a New Transformer
Rare Earths & Corporate Social Responsibility
Research & Development
RE-use, RE-duce, RE-cycle, RE-place
Magnets • Materials • Measurement
Application • Component Developments
Industry News
Rare Earth Crisis Dissected: Securing the Future
Marketplace
Advertising Index
Spontaneous Thoughts: The End of Axial Pressing?

Magnetics Business & Technology - Summer 2012