Nav: Home

Researchers discover link between magnetic field strength and temperature

August 20, 2018

WASHINGTON, D.C., August 20, 2018 -- Researchers recently discovered that the strength of the magnetic field required to elicit a particular quantum mechanical process, such as photoluminescence and the ability to control spin states with electromagnetic (EM) fields, corresponds to the temperature of the material. Based on this finding, scientists can determine a sample's temperature to a resolution of one cubic micron by measuring the field strength at which this effect occurs. Temperature sensing is integral in most industrial, electronic and chemical processes, so greater spatial resolution could benefit commercial and scientific pursuits. The team reports their findings in AIP Advances, from AIP Publishing.

In diamonds, nitrogen atoms can replace carbon atoms; when this occurs next to vacancies in the crystal lattice, it produces useful quantum properties. These vacancies can have a negative or neutral charge. Negatively charged vacancy centers are also photoluminescent and produce a detectable glow when exposed to certain wavelengths of light. Researchers can use a magnetic field to manipulate the spins of the electrons in the vacancies, which alters the intensity of the photoluminescence.

A team of Russian and German researchers created a system that can measure temperatures and magnetic fields at very small resolutions. The scientists produced crystals of silicon carbide with vacancies similar to the nitrogen-vacancy centers in diamonds. Then, they exposed the silicon carbide to infrared laser light in the presence of a constant magnetic field and recorded the resulting photoluminescence.

Stronger magnetic fields make it easier for electrons in these vacancies to transfer between energy spin states. At a specific field strength, the proportion of electrons with spin 3/2 quickly changes, in a process called anticrossing. The brightness of the photoluminescence depends on the proportion of electrons in various spin states, so the researchers could gauge the strength of the magnetic field by monitoring the change in brightness.

Additionally, the luminescence abruptly changes when electrons in these vacancies undergo cross-relaxation, a process where one excited quantum system shares energy with another system in its ground state, bringing both to an intermediate state. The strength of the field needed to induce cross-relaxation is directly tied to the temperature of the material. By varying the strength of the field, and recording when photoluminescence suddenly changed, the scientists could calculate the temperature of the region of the crystal under investigation. The team was surprised to discover that the quantum effects remained even at room temperature.

"This study allows us to create temperature and magnetic field sensors in one device," said Andrey Anisimov, of the Ioffe Physical-Technical Institute of the Russian Academy of Sciences and one of the authors of the paper. Moreover, sensors can be miniaturized to 100 nanometers, which would enable their use in the space industry, geophysical observations and even biological systems. "In contrast to diamond, silicon carbide is already an available semiconductor material, and diodes and transistors are already made from it," Anisimov said.
-end-
The article, "All-optical quantum thermometry based on spin-level cross-relaxation and multicenter entanglement under ambient conditions in SiC," is authored by Andrey N. Anisimov, Victor A. Soltamov, Ilya D. Breev, Roman A. Babunts, Evgeniy N. Mokhov, Georgy V. Astakhov, Vladimir Dyakonov, Dmitri R. Yakovlev, Dieter Suter and Pavel G. Baranov. The article appeared in AIP Advances August 7, 2018, (DOI: 10.1063/1.5037158) and can be accessed at http://aip.scitation.org/doi/full/10.1063/1.5037158.

ABOUT THE JOURNAL

AIP Advances is an open access journal publishing in all areas of physical sciences--applied, theoretical, and experimental. All published articles are freely available to read, download, and share. The journal prides itself on the belief that all good science is important and relevant. Our inclusive scope and publication standards make it an essential outlet for scientists in the physical sciences. See https://aip.scitation.org/adv/info/focus.

American Institute of Physics

Related Magnetic Field Articles:

Earth's last magnetic field reversal took far longer than once thought
Every several hundred thousand years or so, Earth's magnetic field dramatically shifts and reverses its polarity.
A new rare metals alloy can change shape in the magnetic field
Scientists developed multifunctional metal alloys that emit and absorb heat at the same time and change their size and volume under the influence of a magnetic field.
Physicists studied the influence of magnetic field on thin film structures
A team of scientists from Immanuel Kant Baltic Federal University together with their colleagues from Russia, Japan, and Australia studied the influence of inhomogeneity of magnetic field applied during the fabrication process of thin-film structures made from nickel-iron and iridium-manganese alloys, on their properties.
'Magnetic topological insulator' makes its own magnetic field
A team of U.S. and Korean physicists has found the first evidence of a two-dimensional material that can become a magnetic topological insulator even when it is not placed in a magnetic field.
Scientists develop a new way to remotely measure Earth's magnetic field
By zapping a layer of meteor residue in the atmosphere with ground-based lasers, scientists in the US, Canada and Europe get a new view of Earth's magnetic field.
Magnetic field milestone
Physicists from the Institute for Solid State Physics at the University of Tokyo have generated the strongest controllable magnetic field ever produced.
New world record magnetic field
Scientists at the University of Tokyo have recorded the largest magnetic field ever generated indoors -- a whopping 1,200 tesla, as measured in the standard units of magnetic field strength.
Researchers discover link between magnetic field strength and temperature
Researchers recently discovered that the strength of the magnetic field required to elicit a particular quantum mechanical process corresponds to the temperature of the material.
Astronomers observe the magnetic field of the remains of supernova 1987A
For the first time, astronomers have directly observed the magnetism in one of astronomy's most studied objects: the remains of Supernova 1987A (SN 1987A), a dying star that appeared in our skies over thirty years ago.
Watch: Insects also migrate using the Earth's magnetic field
A major international study led by researchers from Lund University in Sweden has proven for the first time that certain nocturnally migrating insects can explore and navigate using the Earth's magnetic field.
More Magnetic Field News and Magnetic Field Current Events

Top Science Podcasts

We have hand picked the top science podcasts of 2019.
Now Playing: TED Radio Hour

Risk
Why do we revere risk-takers, even when their actions terrify us? Why are some better at taking risks than others? This hour, TED speakers explore the alluring, dangerous, and calculated sides of risk. Guests include professional rock climber Alex Honnold, economist Mariana Mazzucato, psychology researcher Kashfia Rahman, structural engineer and bridge designer Ian Firth, and risk intelligence expert Dylan Evans.
Now Playing: Science for the People

#540 Specialize? Or Generalize?
Ever been called a "jack of all trades, master of none"? The world loves to elevate specialists, people who drill deep into a single topic. Those people are great. But there's a place for generalists too, argues David Epstein. Jacks of all trades are often more successful than specialists. And he's got science to back it up. We talk with Epstein about his latest book, "Range: Why Generalists Triumph in a Specialized World".
Now Playing: Radiolab

Dolly Parton's America: Neon Moss
Today on Radiolab, we're bringing you the fourth episode of Jad's special series, Dolly Parton's America. In this episode, Jad goes back up the mountain to visit Dolly's actual Tennessee mountain home, where she tells stories about her first trips out of the holler. Back on the mountaintop, standing under the rain by the Little Pigeon River, the trip triggers memories of Jad's first visit to his father's childhood home, and opens the gateway to dizzying stories of music and migration. Support Radiolab today at Radiolab.org/donate.