Transition metal 'cocktail' helps make brand new superconductors
Concept of high entropy alloys provides a discovery platform for new superconductors
2021-01-09
(Press-News.org) Tokyo, Japan - Researchers from Tokyo Metropolitan University mixed and designed a new, high entropy alloy (HEA) superconductor, using extensive data on simple superconducting substances with a specific crystal structure. HEAs are known to preserve superconducting characteristics up to extremely high pressures. The new superconductor, Co0.2Ni0.1Cu0.1Rh0.3Ir0.3Zr2, has a superconducting transition at 8K, a relatively high temperature for an HEA. The team's approach may be applied to discovering new superconducting materials with specific desirable properties.
It's been over a hundred years since the discovery of superconductivity, where certain materials were found to suddenly show minimal resistance to electrical currents below a transition temperature. As we explore ways to eliminate power waste, a way to dramatically reduce losses in power transmission is a fascinating prospect. But the widespread use of superconductivity is held back by the demands of existing superconductors, particularly the low temperatures required. Scientists need a way to discover new superconducting materials without brute-force trial and error, and tune key properties.
A team led by Associate Professor Yoshikazu Mizuguchi at Tokyo Metropolitan University have been pioneering a "discovery platform" that has already led to the design of many new superconducting substances. Their method is based on high entropy alloys (HEAs), where certain sites in simple crystal structures can be occupied by five or more elements. After being applied to heat resistant materials and medical devices, certain HEAs were found to have superconducting properties with some exceptional characteristics, particularly a retention of zero resistivity under extreme pressures. The team surveys material databases and cutting-edge research and finds a range of superconducting materials with a common crystal structure but different elements on specific sites. They then mix and engineer a structure that contains many of those elements; throughout the crystal, those "HEA sites" are occupied by one of the elements mixed (see Figure 1). They have already succeeded in creating high entropy variants of layered bismuth-sulfide superconductors and telluride compounds with a sodium chloride crystal structure.
In their latest work, they focused on the copper aluminide (CuAl2) structure. Compounds combining a transition metal element (Tr) and zirconium (Zr) into TrZr2 with this structure are known to be superconducting, where Tr could be Sc, Fe, Co, Ni, Cu, Ga, Rh, Pd, Ta, or Ir. The team combined a "cocktail" of these elements using arc melting to create a new HEA-type compound, Co0.2Ni0.1Cu0.1Rh0.3Ir0.3Zr2, which showed superconducting properties. They looked at both resistivity and electronic specific heat, the amount of energy used by the electrons in the material to raise the temperature, and identified a transition temperature of 8.0K. Not only is this relatively high for an HEA-type superconductor, they confirmed that the material had the hallmarks of "bulk" superconductivity.
The most exciting aspect of this is the vast range of other transition metals and ratios that can be tried and tuned to aim for higher transition temperatures and other desirable properties, all without changing the underlying crystal structure. The team hopes their success will lead to more discoveries of new HEA-type superconductors in the near future.
INFORMATION:
This work was supported by a JSPS KAKENHI Grant (Grant Number: 18KK0076) and a grant under the Advanced Research Program of the Human Resources Funds of Tokyo [Grant Number: H31-1].
[Attachments] See images for this press release:
ELSE PRESS RELEASES FROM THIS DATE:
2021-01-09
A new risk-stratification tool which can accurately predict the likelihood of deterioration in adults hospitalised with COVID-19 has been developed by researchers from the UK Coronavirus Clinical Characterisation Consortium (known as ISARIC4C).
Researchers say the online tool, made freely available to NHS doctors from today (Friday 8 January 2021), could support clinicians' decision making - helping to improve patient outcomes and ultimately save lives.
The tool assesses 11 measurements* routinely collected from patients, including age, gender, and physical measurements (such as oxygen levels) along with some standard laboratory tests and calculates a percentage risk ...
2021-01-09
Study of 1,733 patients first diagnosed in Wuhan (China) between January and May followed to June and September.
76% of COVID-19 patients have at least one symptom six months after symptom onset.
Fatigue or muscle weakness is the most common symptom, with sleep difficulties and anxiety or depression also frequently reported.
Lower antibodies against COVID-19 in patients six months after becoming ill compared with during acute infection raises concerns about the possibility of re-infection.
More than three quarters of COVID-19 patients have at least one ongoing symptom six months after initially becoming unwell, according to research published in The Lancet.
The cohort study, looking at long-term effects of COVID-19 infection on people hospitalised ...
2021-01-09
COVID-19 patients admitted to intensive care in the early months of the pandemic were subject to a significantly higher burden of delirium and coma than is typically found in patients with acute respiratory failure. Choice of sedative medications and curbs on family visitation played a role in increasing acute brain dysfunction for these patients.
That's according to an international study published Jan. 8 in The Lancet Respiratory Medicine, led by researchers at Vanderbilt University Medical Center in coordination with researchers in Spain.
The study, which is far the largest of its kind to date, tracks the incidence of delirium and coma in 2,088 COVID-19 patients admitted before April 28, 2020, to 69 adult intensive care units across 14 countries.
ICU delirium is ...
2021-01-08
Hundreds of cancer patients have benefitted from using computer algorithms to manage their symptoms and improve their wellbeing in a unique UK trial.
The early stage colorectal, breast or gynecological cancer patients took part in the trial of the eRAPID system, developed by the University of Leeds, which allowed them to report online symptoms from home and receive instant advice on whether to self-manage or seek medical attention.
Patients reported better symptom control and physical wellbeing in the early weeks of treatment, with the system preventing symptom deterioration in about 9% of patients after 12 weeks. Patients reported more confidence in managing ...
2021-01-08
A year ago, trying to find patients who would agree to see their University of Michigan mental health provider through a video screen felt like pulling teeth.
Only 26 video visits with a few early-adopters had happened in nearly six months, compared with more than 30,000 in-person visits.
But Jennifer Severe, M.D., one of the three psychiatrists who helped launch a test of telehealth initiatives in the U-M's outpatient psychiatry clinic, wasn't about to give up.
She prepared to give a talk at the beginning of April of 2020, hoping to convince more of her colleagues to give telepsychiatry a try, now that a major insurance ...
2021-01-08
Eating a healthy diet, such as the Mediterranean diet, has a positive impact on health, but little is known about the effects of including unhealthy foods in an otherwise healthy diet. Now researchers at Rush University Medical Center have reported diminished benefits of a Mediterranean diet among those with high frequency of eating unhealthy foods. The results of their study were published in Alzheimer's & Dementia: The Journal of the Alzheimer's Association on Jan. 7.
"Eating a diet that emphasizes vegetables, fruit, fish and whole grains may positively affects a person's health," said Puja Agarwal, PhD, a nutritional epidemiologist and assistant professor in the Department of Internal Medicine at Rush Medical College. "But when it is combined with fried food, ...
2021-01-08
In a technique known as DNA origami, researchers fold long strands of DNA over and over again to construct a variety of tiny 3D structures, including miniature biosensors and drug-delivery containers. Pioneered at the California Institute of Technology in 2006, DNA origami has attracted hundreds of new researchers over the past decade, eager to build receptacles and sensors that could detect and treat disease in the human body, assess the environmental impact of pollutants, and assist in a host of other biological applications.
Although the principles of DNA origami are straightforward, the technique's tools and methods for designing new structures are not always easy to grasp and have not been well documented. In addition, scientists new to the method have had no single reference they ...
2021-01-08
Canada is at the forefront of global efforts to end child marriage abroad. Yet this practice remains legal and persists across the country. In Canada, more than 3,600 marriage certificates were issued to children, usually girls, under the age of 18 between 2000 and 2018, according to a new study from researchers at McGill University. In recent years, an increasing number of child marriages have been common-law unions.
Child marriage, defined as formal or informal (common-law) marriage before the age of 18, is a globally-recognized indicator of gender inequality because the negative consequences for ...
2021-01-08
BOSTON - Patients with tuberous sclerosis complex, a genetic disorder characterized by the growth of noncancerous tumors in multiple organs of the body, have limited treatment options. A team led by investigators at Massachusetts General Hospital (MGH) has now shown that gene therapy can effectively treat mice that express one of the mutated genes that cause the disease. The research is published in Science Advances.
The gene, called TSC2, codes for tuberin, a protein that acts to inhibit cell growth and proliferation. When mutations occur in TSC2, resulting in a lack of tuberin in cells, the cells enlarge ...
2021-01-08
ORLANDO, Jan. 8, 2021 - Florida's threatened coral reefs have a more than $4 billion annual economic impact on the state's economy, and University of Central Florida researchers are zeroing in on one factor that could be limiting their survival - coral skeleton strength.
In a new study published in the journal Coral Reefs, UCF engineering researchers tested how well staghorn coral skeletons withstand the forces of nature and humans, such as impacts from hurricanes and divers.
The researchers subjected coral skeletons to higher stresses than those caused by ocean waves, says Mahmoud Omer, a doctoral student in UCF's Department ...
LAST 30 PRESS RELEASES:
[Press-News.org] Transition metal 'cocktail' helps make brand new superconductors
Concept of high entropy alloys provides a discovery platform for new superconductors
