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Tag: Department of Physics

U of A Physicists Determine How a Promising, Lead-Free Material Works

Scientists seeking lead-free materials for use in sensors, actuators and ultrasonic motors have recently focused their efforts on a type of ceramic commonly referred to as BCZT. New research by physicists at the University of Arkansas sheds light on how this material works, providing insights that may result in other lead-free materials being developed as well. The search for a lead-free alternative that generates a strong piezoelectrical response – the conversion of mechanical energy into electrical energy, and vice versa ­– at room temperature is, in part, due to restrictions on hazardous substances in electrical and electronic equipment. BCZT, an abbreviation of the chemical compound barium calcium zirconate titanate, has shown promise, but to date scientists have not fully understood why. “In BCZT, a lead-free material, the piezoelectric response has been measured to be very large while the microscopic origin of the effect remained a matter of debate,” said U of A research associate Yousra Nahas. “It became important to unveil the origin of the effect in order to better gear the properties of this material to the technological challenges.” In a paper published June 20 in the journal Nature Communications, U of A researchers Nahas, Alireza Akbarzadeh, Sergei Prosandeev and Raymond Walter, along with Distinguished Professor of physics Laurent Bellaiche, created an atomic-level model of the BCZT material to unlock its piezoelectric secrets. They determined that its piezoelectric...

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Physicists Gain New Understanding of Quantum Cooling Process

New research at the University of Arkansas is helping physicists better understand optomechanical cooling, a process that is expected to find applications in quantum technology. Scientists have long understood that applying a properly tuned light field to a macroscopic (visible to the naked eye) object – in this case a mechanical oscillator – results in cooling the object. The process, optomechanical cooling, happens when pressure from photons (particles of light) converts energy stored in the object in the form of thermal phonons (particles of sound) into photons. Ideally, the process would cool the object to its pure quantum state at which all thermal energy is removed. In reality, the quantum state cannot be achieved due to noise perturbations in the environment. In their work, U of A researchers defined the cooling limit, which advances understanding of the process. Their findings were reported in an article titled, “Radiation Pressure Cooling as a Quantum Dynamical Process,” published June 9 in the journal Physical Review Letters. “Like any evolution to a stable state, cooling a mechanical oscillator takes time and, in contrast to what was previously understood, the speed of the process decides what state will be finally achieved,’’ said Bing He, first author of the paper and a research in the Department of Physics. “Our dynamical picture clarifies how an optomechanical system undergoes the transition from heating to cooling and vice...

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Graphine, the 2-Dimensional Powerhouse

https://researchfrontiers.uark.edu/wp-content/uploads/sites/210/2017/04/Paul-Thibado-final.mp3   Short Talks From The Hill is a podcast highlighting research and scholarly work across the University of Arkansas campus. Each segment features a university researcher discussing his or her work. In this episode, Paul Thibado, professor of physics in the J. William Fulbright College of Arts and Sciences, discusses graphene, a two-dimensional material that is a mere single atom in thickness, and its potential role in the development of next-generation of electronic devices. Chris Branam: Hello and welcome to Short Talks from the Hill, a podcast from the University of Arkansas.  I’m Chris Branam. On this episode, Paul...

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Is Anything Tough Enough to Survive on Mars?

Researchers at the University of Arkansas recently took a step toward answering a question for the ages: Is there life on Mars? Answer: they can’t rule it out. Two recent publications suggest that life, in the form of ancient, simple organisms called methanogens, could survive the harsh conditions found near the surface of Mars, and deep in its soils. Using methanogens to test for survivability is particularly relevant because scientists have detected their byproduct, methane, in the Martian atmosphere. On Earth, methane is strongly associated with organic matter, though there are non-organic sources of the gas, including volcanic eruptions....

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