Putting the pressure on platinum

August 05, 2016

Superconductors are materials that, when cooled below a certain temperature, conduct free-flowing electricity without it being impeded by resistance. They are used in magnetic resonance imaging (MRI) machines, magnetic levitation trains and particle accelerators like the Large Hadron Collider. Researchers are constantly on the lookout for materials that can become superconducting at higher-than-currently-possible temperatures and lower costs.

A team of researchers from Japan's Hokkaido University along with colleagues at the Kyushu Institute of Technology, NEC Corporation, Keio University and the National Institute for Materials Science have developed a novel superconducting material based on platinum, which was, until recently, thought to be unsuitable as a superconducting material.

The material was developed by mixing lanthanum (La), platinum (Pt) and arsenic (As) powders in a ratio of 1:5:1 and compressing them into pellets. These were then heated to 500°C for ten hours. The resultant material was ground and re-pelletized, then heated at 1000°C for an hour at various pressures. The team found that the final product (LaPt5As ) was non-superconducting at a pressure of five gigapascals (GPa) (equivalent to 50,000 bars of pressure), but became superconducting at 10 GPa, only to return to a non-superconductive state at 15 GPa.

The researchers examined the crystal structure of the superconducting LaPt5As. They revealed that platinum atoms formed multiple layers which piled up as high as 6 nm, the highest among metal superconductor. They also found that lanthanum and arsenic atoms separated platinum layers from each other in a way, they speculate, which weakens the interaction between platinum electrons, allowing them to flow more freely and resulting in the superconducting property.

Future research that determines the detailed crystal structure of the non-superconducting phases of LaPt5sAs will aid in the understanding of the mechanism that causes the material to become superconducting at 10 GPa, the researchers say.

High-pressure synthesis (over 10 GPa) is not a commonly used method in the field of materials science, write the researchers in their study published in the Journal of the American Chemical Society. This research shows there is room for further exploration of unknown phases induced by high pressure in a variety of materials, they say.

Hokkaido University

Related Arsenic Articles from Brightsurf:

New map reveals global scope of groundwater arsenic risk
Up to 220 million people worldwide, with approximately 94% of them in Asia, could be at risk of drinking well water containing harmful levels of arsenic, a tasteless, odorless and naturally occurring poison.

River-groundwater hot spot for arsenic
Naturally occurring groundwater arsenic contamination is a problem of global significance, particularly in South and Southeast Asian aquifers.

Natural organic matter influences arsenic release into groundwater
Millions of people worldwide consume water contaminated with levels of arsenic that exceed those recommended by the World Health Organization.

New study finds inaccuracies in arsenic test kits in Bangladesh
Researchers at the University of Michigan have raised serious concerns with the performance of some arsenic test kits commonly used in Bangladesh to monitor water contamination.

Bayreuth researchers discover new arsenic compounds in rice fields
University of Bayreuth researchers, together with scientists from Italy and China, have for the first time sys-tematically investigated under which conditions, and to what extent, sulphur-containing arsenic com-pounds are formed in rice-growing soils.

Kids rice snacks in Australia contain arsenic above EU guidelines: Study
Three out of four rice-based products tested have concentrations of arsenic that exceed the EU guideline for safe rice consumption for babies and toddlers.

Arsenic in drinking water may change heart structure
Among young adults, drinking water contaminated with arsenic may lead to structural changes in the heart that raise their risk of heart disease.

Arsenic-breathing life discovered in the tropical Pacific Ocean
In low-oxygen parts of the ocean, some microbes are surviving by getting energy from arsenic.

Parboiling method reduces inorganic arsenic in rice
Contamination of rice with arsenic is a major problem in some regions of the world with high rice consumption.

UN University compares technologies that remove arsenic from groundwater
A UN University study compares for the first time the effectiveness and costs of many different technologies designed to remove arsenic from groundwater -- a health threat to at least 140 million people in 50 countries.

Read More: Arsenic News and Arsenic Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.