Nav: Home

Rice U. lab surprised by ultraflat magnets

October 11, 2017

Substituting atoms in the process of making two-dimensional alloys not only allows them to be customized for applications but also can make them magnetic, according to Rice University scientists and their collaborators.

A new paper in Advanced Materials outlines how researchers at Rice, Oak Ridge National Laboratory, the University of Southern California (USC) and Kumamoto University in Japan used chemical vapor deposition (CVD) to make atom-thick sheets and, in the same step, tailor their properties by adding other elements through a process known as doping.

They discovered by surprise that they could also give the 2-D sheets magnetic properties.

The labs worked with transition metal dichalcogenides, alloys that combine a transition metal and chalcogen atoms into a single material. Transition metals are stable elements that fall in the middle of the periodic table. Chalcogens include sulfur, selenium and tellurium, also neighbors to each other in the table.

By adding a dopant element to the mix during CVD, the researchers showed it was possible to rearrange the atoms on the resulting 2-D crystal sheets. They demonstrated several different configurations and found they could replace some atoms outright with the dopant. These physical changes led to changes in the mechanical and electronic properties of the flat crystals, said co-author and Rice postdoctoral researcher Chandra Sekhar Tiwary.

The Rice lab of Pulickel Ajayan led the project to test theories by USC researchers who calculated that doping the materials would force a phase transition in the 2-D crystals. The Rice team confirmed the theory that adding rhenium in various amounts to molybdenum diselenide during growth would allow them to tailor its properties by changing its atomic structure. The magnetic signatures were a bonus.

"Usually, when you make a magnetic material, you start with magnetic elements like iron or cobalt," said graduate student and co-lead author Amey Apte. "Rhenium, in bulk, is not a magnetic material, but it turns out it is in certain combinations at the atomic scale. It worked fantastically in this case."

The researchers said the magnetic properties they discovered could make the 2-D alloys of interest to those who design spintronic devices.
-end-
Former Rice postdoctoral researcher Vidya Kochat is co-lead author of the paper. Co-authors are Rice graduate student Sandhya Susarla; postdoctoral researcher Jordan Hachtel and staff scientist Juan Carlos Idrobo of Oak Ridge; graduate student Hiroyuki Kumazoe of the University of Southern California and Kumamoto University; postdoctoral researcher Aravind Krishnamoorthy and professors Priya Vashishta, Rajiv Kalia and Aiichiro Nakano of the University of Southern California; and Fuyuki Shimojo of Kumamoto University. Ajayan is chair of Rice's Department of Materials Science and NanoEngineering, the Benjamin M. and Mary Greenwood Anderson Professor in Engineering and a professor of chemistry.

The Computational Materials Science Program funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, supported the research.

Read the abstract at http://onlinelibrary.wiley.com/doi/10.1002/adma.201703754/full

This news release can be found online at http://news.rice.edu/2017/10/10/rice-u-lab-surprised-by-ultraflat-magnets/

Follow Rice News and Media Relations via Twitter @RiceUNews

Related materials:

Ajayan Research Group: http://ajayan.rice.edu

Rice Department of Materials Science and NanoEngineering: https://msne.rice.edu

Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,879 undergraduates and 2,861 graduate students, Rice's undergraduate student-to-faculty ratio is 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is ranked No. 1 for quality of life and for lots of race/class interaction and No. 2 for happiest students by the Princeton Review. Rice is also rated as a best value among private universities by Kiplinger's Personal Finance. To read "What they're saying about Rice," go to http://tinyurl.com/RiceUniversityoverview.

Rice University

Related Rice Articles:

High-protein rice brings value, nutrition
A new advanced line of rice, with higher yield, is ready for final field testing prior to release.
Rice plants engineered to be better at photosynthesis make more rice
A new bioengineering approach for boosting photosynthesis in rice plants could increase grain yield by up to 27 percent, according to a study publishing January 10, 2019 in the journal Molecular Plant.
Can rice filter water from ag fields?
While it's an important part of our diets, new research shows that rice plants can be used in a different way, too: to clean runoff from farms before it gets into rivers, lakes, and streams.
Rice plants evolve to adapt to flooding
Although water is essential for plant growth, excessive amounts can waterlog and kill a plant.
Breeding better Brazilian rice
Rice production in Brazil is a multi-billion-dollar industry. It employs hundreds of thousands of people, directly and indirectly.
Breakthrough in battle against rice blast
Scientists have found a way to stop the spread of rice blast, a fungus that destroys up to 30% of the world's rice crop each year.
More rice, please: 13 rice genomes reveal ways to keep up with ever-growing population
Rice provides 20% of daily calories consumed globally. We will need more as population grows toward 9-10 billion by 2050.
Ancient rice heralds a new future for rice production
Growing in crocodile infested billabongs in the remote North of the country, Australia's wild rice has been confirmed as the most closely related to the ancient ancestor of all rices.
2-faced 2-D material is a first at Rice
Rice University materials scientists replace all the atoms on top of a three-layer, two-dimensional crystal to make a transition-metal dichalcogenide with sulfur, molybdenum and selenium.
Multi-nutrient rice against malnutrition
ETH researchers have developed a new rice variety that not only has increased levels of the micronutrients iron and zinc in the grains, but also produces beta-carotene as a precursor of vitamin A.
More Rice News and Rice Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Teaching For Better Humans 2.0
More than test scores or good grades–what do kids need for the future? This hour, TED speakers explore how to help children grow into better humans, both during and after this time of crisis. Guests include educators Richard Culatta and Liz Kleinrock, psychologist Thomas Curran, and writer Jacqueline Woodson.
Now Playing: Science for the People

#556 The Power of Friendship
It's 2020 and times are tough. Maybe some of us are learning about social distancing the hard way. Maybe we just are all a little anxious. No matter what, we could probably use a friend. But what is a friend, exactly? And why do we need them so much? This week host Bethany Brookshire speaks with Lydia Denworth, author of the new book "Friendship: The Evolution, Biology, and Extraordinary Power of Life's Fundamental Bond". This episode is hosted by Bethany Brookshire, science writer from Science News.
Now Playing: Radiolab

Space
One of the most consistent questions we get at the show is from parents who want to know which episodes are kid-friendly and which aren't. So today, we're releasing a separate feed, Radiolab for Kids. To kick it off, we're rerunning an all-time favorite episode: Space. In the 60's, space exploration was an American obsession. This hour, we chart the path from romance to increasing cynicism. We begin with Ann Druyan, widow of Carl Sagan, with a story about the Voyager expedition, true love, and a golden record that travels through space. And astrophysicist Neil de Grasse Tyson explains the Coepernican Principle, and just how insignificant we are. Support Radiolab today at Radiolab.org/donate.