Hexbyte Glen Cove New family of ferroelectric materials raises possibilities for improved information and energy storage thumbnail

Hexbyte Glen Cove New family of ferroelectric materials raises possibilities for improved information and energy storage

Hexbyte Glen Cove

Part of the process of creating ferroelectric magnesium-substituted zinc oxide thin films includes: (left) Image showing thin film being sputter-deposited from metal sources; (center) ferroelectric hysteresis loops of thin-film capacitors showing two remanent polarization states at zero field; (right) atomic force microscope image showing a smooth surface at the nanometer scale and a very fine-grained and fiber-textured microstructure. Credit: Materials Research Institute, Penn State

A new family of materials that could result in improved digital information storage and uses less energy may be possible thanks to a team of Penn State researchers who demonstrated ferroelectricity in magnesium-substituted zinc oxide.

Ferroelectric materials are spontaneous electricly polarized bcause negative and positive charges in the material tend toward opposite sides and with the application of an external electric field reorient. They can be affected by physical force, which is why they are useful for push-button ignitors such as those found in gas grills. They can also be used for data storage and memory, because they remain in one polarized state without additional power and so are low-energy digital storage solutions.

“We’ve identified a new family of materials from which we can make tiny capacitors and we can set their polarization orientation so that their surface charge is either plus or minus,” said Jon-Paul Maria, Penn State professor of materials science and engineering, and co-author of the paper published in the Journal of Applied Physics. “That setting is nonvolatile, meaning we can set the capacitor to plus, and it stays plus, we can set it to minus, it stays minus. And then we can come back and identify how we set that capacitor, at say, an hour ago.”

This ability could enable a form of digital storage that does not use as much electricity as other forms.

“This type of storage requires no additional energy,” Maria said. “And that’s important because many of the computer memories that we use today require additional electricity to sustain the information, and we use a substantial amount of the American energy budget on information.”

The new materials are made with magnesium-substituted thin films. The film was grown via sputter deposition, a process where argon ions are accelerated towards the target materials, impacting it with a high enough energy to break atoms free from the target that contains magnesium and zinc. The freed magnesium and zinc atoms travel in a vapor phase until they react with oxygen and collect on a platinum-coated aluminum oxide substrate and form the thin films.

Researchers have studied magnesium-substituted zinc oxide as a method of increasing zinc oxide’s band gap, a key material characteristic that is important for creating semiconductors. However, the material was never explored for ferroelectricity. Nonetheless, the researchers believed that the material could be made ferroelectric, based on an idea of “ferroelectrics everywhere” posited by Maria and Susan Trolier-McKinstry, Evan Pugh University Professor, Steward S. Flaschen Professor of Ceramic Science and Engineering, and co-author on the paper.

“Generally speaking, ferroelectricity often occurs in minerals that are complicated from a structure and chemistry point of view,” Maria said. “And our team proposed the idea about two years ago, that there are other simpler crystals in which this useful phenomenon could be identified, as there were some clues that made us propose this possibility. To say ‘ferroelectrics everywhere’ is a bit of a play on words, but it captures the idea that there were materials around us that were giving us hints, and we were ignoring those hints for a long time.”

Trolier-McKinstry’s research career has focused on ferroelectrics, including the search for better with different properties. She noted that the University of Kiel in Germany had found the very first of this surprising type of ferroelectric materials in 2019 in nitrides, but that she and Maria have demonstrated comparable behavior in an oxide.

Part of the process Trolier-McKinstry and Maria’s group followed is developing a figure of merit, a quantity used in sciences such as analytical chemistry and materials research that characterizes the performance of a device, material or method relative to alternatives.

“As we look at any application for material, we often devise a figure of merit that says what combination of materials properties we would need for any given application to make it as effective as possible,” said Trolier-McKinstry. “And this new family of ferroelectrics, it gives us whole new possibilities for those figures of merit. It’s very appealing for applications that historically we haven’t had great materials sets for, so this kind of new materials development tends to spark new applications.”

An added benefit of the magnesium-substituted zinc oxide thin films is how they can be deposited at much than other ferroelectric materials.

“The overwhelming majority of electronic materials are prepared with the assistance of high temperatures, and high temperatures means anywhere from 300 to 1000 degrees Celsius (572 to 1835 degrees Fahrenheit),” said Maria. “Whenever you make materials at elevated temperatures, it comes with a lot of difficulties. They tend to be engineering difficulties, but nonetheless they make everything more challenging. Consider that every capacitor needs two electrical contacts—if I prepare my ferroelectric layer at high temperatures on at least one of these contacts, at some point an unwanted chemical reaction will occur. So, when you can make things at low temperatures, you can integrate them much more easily.”

The next step for the new materials is making them into capacitators that are approximately 10 nanometers thick and 20 to 30 nanometers in lateral dimensions, which is a difficult engineering challenge. The researchers need to create a way to control the growth of the materials so there are no issues such as imperfections in the materials. Trolier-McKinstry said that solving these issues will be key to whether these materials are usable in new technologies—cell phones with chips that use much less energy, allowing sustained operation for a week or more.

“When developing , you have to find out how they fail, and then understand how to mitigate those failure mechanisms,” Trolier-McKinstry said. “And for every single application, you need to decide what are the essential properties, and how will they evolve over time. And until you’ve made some measurements on that, you don’t know what the big challenges are going to be, and the reliability and manufacturability are huge in terms of whether this material ends up in your cell phone in five years.”

More information:
Kevin Ferri et al, Ferroelectrics everywhere: Ferroelectricity in magnesium substituted zinc oxide thin films, Journal of Applied Physics (2021). DOI: 10.1063/5.0053755

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Hexbyte Glen Cove Is your family 'CO safe' when big storms hit? thumbnail

Hexbyte Glen Cove Is your family ‘CO safe’ when big storms hit?

Hexbyte Glen Cove

(HealthDay)—If you live in the path of hurricanes , the U.S. Consumer Product Safety Commission (CPSC) is urging you to be prepared.

Deaths from (CO) poisoning, fires and are common during severe weather events, according to the CPSC.

Hurricane season in North America runs from June 1 through Nov. 30. The National Oceanic and Atmospheric Administration (NOAA) has upped averages from 12 to 14 named storms and from six to seven hurricanes. Its official forecast is due out next week, but Colorado State University has already forecast a dire season, with 17 named storms and eight hurricanes, four of them major ones.

“Millions of Americans who are still dealing with the stress of the global COVID-19 pandemic also live in regions prone to devastating hurricanes and severe storms,” said Robert Adler, acting chairman of the CPSC. “It only takes one hurricane to cause massive destruction and loss of life. Be prepared, stay informed, and keep safe before and after storms.”

The CPSC said that people who rely on portable generators when power is out need to be cautious because the devices carry the risk of CO poisoning and fire. More than 400 people die from CO poisoning each year in the United States, according to the U.S. Centers for Disease Control and Prevention. Carbon monoxide from a can kill within minutes.

To stay safe, follow these tips:

  • Before the storm, install battery-operated CO alarms or CO alarms with battery backup in your home.
  • Have smoke alarms on every level of your home, inside bedrooms and outside sleeping areas.
  • Test your alarms every month.
  • Be sure your generator is properly maintained.
  • Have flashlights and extra batteries on hand.
  • Use portable generators outside only. Keep them at least 20 feet from the house.
  • Direct the generator’s exhaust away from the home.
  • Never use a portable generator inside the house, garage, basement, crawlspace, shed or on the porch. Opening doors or windows will not provide enough ventilation to prevent CO buildup.
  • CO poisoning can happen so fast that people may become unconscious before recognizing the symptoms of nausea, dizziness or weakness.
  • If CO or smoke alarms go off, get outside immediately and then call 911.

Other hazards during season include:

Charcoal: Don’t use it indoors as it can produce deadly levels of CO. Never cook on a charcoal grill in a garage, even with the door open.

Candles: Use flashlights instead. If you do use candles, do not burn them on or near anything that can catch fire. Never leave burning candles unattended. Put candles out when you leave the room and before sleeping.

Wet appliances: Look for signs that appliances have gotten wet. Discard unplugged gas or electric appliances that have been wet, because they can cause shocks and fires. Do not touch appliances that are still plugged in.

Before using appliances: Have a professional or your gas or electric company evaluate your home and replace gas control valves, electrical wiring, circuit breakers and fuses that have been underwater.

Gas leaks: If you smell or hear gas, get out of the house immediately. Do not turn lights on or off, or use electrical equipment, including a phone. Once safely outdoors and away from the house, contact the gas company.

More information:
Learn more about hurricane preparedness at the American Red Cross.

Copyright © 2021 HealthDay. All rights reserved.

Is your family ‘CO safe’ when big storms hit? (2021, May 16)
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Hexbyte Glen Cove Black hole 'family portrait' is most detailed to date thumbnail

Hexbyte Glen Cove Black hole ‘family portrait’ is most detailed to date

Hexbyte Glen Cove

A collection of masses for a wide range of compact objects. The graphic shows black holes (blue), neutron stars (orange) and compact objects of uncertain nature (gray) detected through gravitational waves. Each compact binary merger corresponds to three compact objects: the two coalescing objects and the final merger remnant. Credit: Aaron M. Geller, Northwestern University and Frank Elavsky, LIGO-Virgo

An international research collaboration including Northwestern University astronomers has produced the most detailed family portrait of black holes to date, offering new clues as to how black holes form. An intense analysis of the most recent gravitational-wave data available led to the rich portrait as well as multiple tests of Einstein’s theory of general relativity. (The theory passed each test.)

The team of scientists who make up the LIGO Scientific Collaboration (LSC) and the Virgo Collaboration is now sharing the full details of its discoveries. This includes new gravitational-wave detection candidates which held up to scrutiny—a whopping total of 39, representing a variety of and —and new discoveries as a result of combining all the observations. The 39 events averaged more than one per week of observing.

The observations could be a key piece in solving the many mysteries of exactly how interact. A better understanding of how binary stars evolve has consequences across astronomy, from exoplanets to galaxy formation.

Details are reported in a trio of related papers which will be available in pre-print on Oct. 28 at arxiv.org. The studies also are being submitted to peer-reviewed journals.

The gravitational-wave signals on which the studies are based were detected during the first half of the third observing run, called O3a, of the National Science Foundation’s Laser Interferometry Gravitational-wave Observatory (LIGO), a pair of identical, 4-kilometer-long interferometers in the United States, and Virgo, a 3-kilometer-long detector in Italy. The instruments can detect gravitational-wave signals from many sources, including colliding black holes and colliding neutron stars.

“Gravitational-wave astronomy is revolutionary—revealing to us the hidden lives of black holes and neutron stars,” said Christopher Berry, an LSC member and author of the papers. “In just five years we have gone from not knowing that binary black holes exist to having a catalog of over 40. The third observing run has yielded more discoveries than ever before. Combining them with earlier discoveries paints a beautiful picture of the universe’s rich variety of binaries.”

This illustration shows the merger of two black holes and the gravitational waves that ripple outward as the black holes spiral toward each other. Credit: LIGO/T. Pyle

Berry is the CIERA Board of Visitors Research Professor in Northwestern’s CIERA (Center for Interdisciplinary Exploration and Research in Astrophysics) and a lecturer at the University of Glasgow. Other Northwestern authors include CIERA members Maya Fishbach and Chase Kimball. CIERA is home to a broad group of researchers in theory, simulation and observation who study black holes, neutron stars, white dwarfs and more.

As a member of the collaboration, Northwestern researchers analyzed data from the gravitational-wave detectors to infer the properties of detected black hole and neutron star binaries and to provide an astrophysical interpretation of these discoveries.

The papers are summarized as follows:

  • The “catalog paper” details the detections of black holes and neutron stars from the first half of O3a, bringing the total number of detection candidates for that period to 39. This number vastly exceeds detections from the first two observing runs. (The first run had three gravitational-wave detections, and the second had eight.) Previously announced detections from O3a include a mystery object in the mass gap (GW190814) and the first-of-its-kind intermediate mass black hole (GW190521).
  • In the “populations paper,” the researchers reconstructed the distribution of masses and spins of the black hole population and estimated the merger rate for binary neutron stars. The results will help scientists understand the detailed astrophysical processes which shape how these systems form. This improved understanding of the mass distribution of black holes and knowing that black hole spins can be misaligned suggests there could be multiple ways for binary black holes to form.
  • Using the set of detections reported in the catalog paper, the researchers conducted detailed analysis by combining everything together. In what they call the “testing general relativity paper,” the authors placed constraints on Einstein’s . The theory passed with flying colors, and they updated their best measurements on potential modifications.

“So far, LIGO and Virgo’s third observing run has yielded many surprises,” said Fishbach, a NASA Einstein Postdoctoral Fellow and LSC member. “After the second observing run, I thought we’d seen the whole spectrum of binary black holes, but the landscape of black holes is much richer and more varied than I imagined. I’m excited to see what future observations will teach us.”

Fishbach coordinated writing of the populations paper which outlines what the collaboration has learned about the properties of the family of merging black holes and neutron stars.

This illustration generated by a computer model shows multiple black holes found within the heart of a dense globular star cluster. Credit: Aaron M. Geller, Northwestern University/CIERA

Berry helped coordinate analysis as part of a global team to infer the properties of the detections, and he served as an LSC Editorial Board reviewer for the catalog and testing general relativity papers.

Graduate student Chase Kimball, an LSC member, contributed calculations of the rates of mergers to the populations paper. Kimball is co-advised by Berry and Vicky Kalogera, the principal investigator of Northwestern’s LSC group, director of CIERA and the Daniel I. Linzer Distinguished University Professor of Physics and Astronomy in the Weinberg College of Arts and Sciences.

The LIGO and Virgo detectors finished their latest observing run this past March. The data analyzed in these three papers were collected from April 1, 2019, to Oct. 1, 2019. Researchers are in the process of analyzing data from the second half of the observing run, O3b.

The detectors are scheduled to resume observing next year after work is done to increase their detection range.

“Merging black hole and neutron star binaries are a unique laboratory,” Berry said. “We can use them to study both gravity—so far Einstein’s general relativity has passed every test —and the astrophysics of how massive live their lives. LIGO and Virgo have transformed our ability to observe these binaries, and, as our detectors improve, the rate of discovery is only going to accelerate.”

More information:
The “populations” paper is titled “Population properties of compact objects from the second LIGO-Virgo Gravitational-Wave Transient Catalog.”

The “catalog” paper is titled “GWTC-2: Compact Binary Coalescences Observed by LIGO and Virgo During the First Half of the Third Observing Run.”

The “testing general relativity” paper is titled “Tests of General Relativity with Binary Black Holes from the second LIGO-Virgo.”

Black hole ‘family portrait’ is most detailed to date (2020, October 29)
retrieved 29 October 2020
from https://phys.org/news/2020-10-black-hole-family-portrait-date.html

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