Spintronics

A team of scientists led by Associate Professor Yang Hyunsoo from the National University of Singapore’s (NUS) Faculty of Engineering has invented a novel ultra-thin multilayer film which could harness the properties of tiny magnetic whirls, known as skyrmions, as information carriers for storing and processing data (nanocomputer) on magnetic media. The nano-sized thin film, which was developed in collaboration with researchers from Brookhaven National Laboratory, Stony Brook University, and Louisiana State University, is a critical step towards the design of data storage devices that use less power and work faster than existing memory technologies.

The digital transformation has resulted in ever-increasing demands for better processing and storing of large amounts of data, as well as improvements in hard drive technology. Since their discovery in magnetic materials in 2009, skyrmions, which are tiny swirling magnetic textures only a few nanometres in size, have been extensively studied as possible information carriers in next-generation data storage and logic devices.

Skyrmions have been shown to exist in layered systems, with a heavy metal placed beneath a ferromagnetic material. Due to the interaction between the different materials, an interfacial symmetry breaking interaction, known as the Dzyaloshinskii-Moriya interaction (DMI), is formed, and this helps to stabilise a skyrmion. However, without an out-of-plane magnetic field present, the stability of the skyrmion is compromised. In addition, due to its tiny size, it is difficult to image the nano-sized materials. The NUS team found that a large DMI could be maintained in multilayer films composed of cobalt and palladium, and this is large enough to stabilise skyrmion spin textures.

skyrmionsThis experiment not only demonstrates the usefulness of L-TEM in studying these systems, but also opens up a completely new material in which skyrmions can be created. Without the need for a biasing field, the design and implementation of skyrmion based devices are significantly simplified. The small size of the skyrmions, combined with the incredible stability generated here, could be potentially useful for the design of next-generation spintronic devices that are energy efficient and can outperform current memory technologies,” explains Professor Yang .

The invention was reported in the journal Nature Communications.

Source: http://news.nus.edu.sg

Why North Atlantic Tuna Is Less Toxic ?

In a piece of welcome news for seafood lovers, a Stony Brook-led research team has found declining levels of mercury in bluefin tuna caught in the North Atlantic over the past decadeMercury is a neurotoxin harmful to humans, and tuna provide more mercury to humans than any other source.

A study led by Stony Brook University’s School of Marine and Atmospheric Sciences (SoMAS) and published in Environmental Science & Technology provides a new data set, the largest of its kind, of mercury concentrations in Atlantic bluefin tuna. The data demonstrate that, while tissue concentrations were higher than in most other fish species, there has been a consistent decline in mercury concentrations in these tuna over time, regardless of age of the fish.

blue-sea

KEY FINDINGS:

The researchers measured mercury concentrations from the tissue of 1,292 bluefin tuna caught between 2004 and 2012

  • Over the eight-year period, mercury levels in the fish fell 19 percent.
  • Mercury concentrations were generally high, and were highest in the largest, oldest fish; no differences were noted between males and females.
  • Mercury in the air over the North Atlantic fell 20 percent from 2001 to 2009.
  • Global levels of mercury emissions have fallen 2.8 percent a year from 1990 to 2007.

The rate of decline parallels the declines – over the same time period — of mercury emissions, mercury levels in North Atlantic air, and mercury concentrations in North Atlantic seawater. Authors of the study include Stony Brook’s Cheng-Shiuan Lee, a Ph.D student in chemical/biological oceanography, and Nicholas S. Fisher, Distinguished Professor & Director, Consortium for Inter-Disciplinary Environmental Research at SoMAS.

According Fisher, the finding appears to indicate that changes in mercury levels in fish tissue respond in real time to changes in mercury loadings into the ocean. The study suggests that mercury levels may be improving as a result of declining coal use, reducing emissions that drift over the Atlantic.

Source: http://www.stonybrook.edu/

How To Stop The Spread Of Breast Cancer

A breakthrough technology that harnesses manmade nanoparticles could one day become an important new weapon in the fight against cancer. The technique, which appeared to successfully stop the spread of breast cancer in mice, was unveiled by scientists from the Cold Spring Harbor Laboratory, Dana-Farber Cancer Institute, Stony Brook University, and a host of other research institutions in the journal Science Translational Medicine.

Next-generation cancer fighting therapies on the market today use the body’s immune system to combat tumors, as does experimental technology like CRISPR gene-editing. But the new nanotech has a different target: The cells that actually help cancer metastasize and spread throughout the body. These immune cells, which are meant to ward off infections, create structures called neutrophil extracellular traps (NETs) that help them fight bacteria. But NETs can actually wind up helping spread the cancer by creating tissue openings that cancerous cells can exploit, study co-author Mikala Egeblad explained.

 breast-cancer-cells

A high magnification of an intact neutrophil (yellow arrow) and a NET (white arrow)

So the researchers created a new particle coated with a special enzyme that can kill these cells before the cancer can use them to metastasize. The results were modest, but promising: Three out of the nine mice given the nanoparticle showed no evidence of breast cancer progression, while all mice in the control group continued to worsen.