Saturday, October 22, 2016

Archive >  April 2013 Issue >  Front Page News > 

New NIST Microscope Measures Nanomagnets
Gaithersburg, MD — Researchers at the National Institute of Standards and Technology (NIST) have developed a new microscope able to view and measure an important but elusive property of the nanoscale magnets used in an advanced, experimental form of digital memory. The new instrument already has demonstrated its utility with initial results that suggest how to limit power consumption in future computer memories.

NIST's heterodyne magneto-optic microwave microscope, or H-MOMM, can measure collective dynamics of the electrons' spins — the basic phenomenon behind magnetism — in individual magnets as small as 100 nanometers in diameter. Nanomagnets are central components of low-power, high-speed "spintronic" computer memory, which might soon replace conventional random-access memory. Spintronics relies on electrons behaving like bar magnets, pointing in different directions to manipulate and store data, whereas conventional electronics rely on charge.

"The measurement technique is entirely novel, the capability that it has enabled is unprecedented, and the scientific results are groundbreaking," project leader Tom Silva says.

Spin Relaxation Process
As described in a new paper, NIST researchers used the H-MOMM to quantify, for the first time, the spin relaxation process — or damping — in individual nanomagnets. Spin relaxation is related to how much energy is required to switch a unit of spintronic memory between a 0 and a 1, the bits used to represent data. (See: H.T. Nembach, J.M. Shaw, C.T. Boone and T.J. Silva. "Mode- and size-dependent Landau-Lifshitz damping in magnetic nanostructures: Evidence for non-local damping." Physical Review Letters. 110, 117201. Published March 12, 2013.)

The nanomagnets used in experimental spintronic systems are too big to yield their secrets to conventional atomic physics tools yet too small for techniques used with bulk materials. Until now, researchers have been forced to measure the average damping from groups of nanomagnets. The new microscope has enabled NIST researchers to study, in detail, the ups and downs of spin excitation in individual magnets made of a layer of a nickel-iron alloy on a sapphire base.

Combining Microwave and Optical
The H-MOMM combines optical and microwave techniques. Two green laser beams are merged to generate microwaves, which excite "spin waves" — magnetic oscillations that vary with position across an individual nanomagnet, like waves in a bathtub. Polarized light from one laser is used to analyze the excitation pattern. By measuring excitation as a function of magnetic field and microwave frequency, researchers can deduce the damping of various spin waves in each nanomagnet.

Measurement and control of magnetic damping is crucial for spintronics, because the smaller the damping, the less energy is required to store a bit of data, and the less power a device requires to operate. The NIST study suggests that designing spintronic devices to have uniform spin waves could dramatically reduce the energy required to write a bit.

The new microscope is one outcome of an ongoing NIST effort to develop methods for measuring defects in magnetic nanostructures. At extremely small scales, defects dominate and can disrupt magnetic device behavior, resulting in errors in reading and writing information.


Add your comment:

Full Name:

World PCB Production in 2015 Estimated at $58.6 Billion
BANNOCKBURN, IL - The world market for printed circuit boards (PCBs) reached an estimated $58.6 billion in value in 2015 according to IPC’s  World PCB Production Report for the Year 2015. This represents a nominal decrease of 2.7 percent from 2014, but factoring out the effects of exchange rate fluctuations, the growth of PCB output was actually up 2.0 percent in real terms.

Session 4 of IPC & SMTA's Conference to Focus on Ultra-Thin or Nanocoatings
ROSEMONT, IL - Industry-leading associations IPC and SMTA jointly announce the High-Reliability Cleaning and Conformal Coating Conference, scheduled to take place October 25-27, 2016 at Hyatt Rosemont, Rosemont, Illinois. The conference is focused on best practices for designing, cleaning and coating highly dense electronic assemblies to assure reliability in today’s mobile society.

Unigen Hires Industry Veteran as Director of Sales for EMS
FREMONT, CA - Unigen Corporation, a leading global provider of electronics manufacturing services (EMS), announces that Kristen Young has joined its team as Director of Sales.

In this role, Kristen is responsible for growing the EMS portion of Unigen’s business for both the Newark and Vietnam factories. Additionally, she will focus on developing and maintaining long-term business relationships, and will act as a liaison between customers and Unigen to deliver the highest quality product in a very competitive market.

search login