Heisenberg said extreme magnetism would make nothingness bend light. A dead star just proved he was right.
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Embedded platinum channels bring nanoscale spin-based thermoelectric conversion to bulk materials
A joint research team from NIMS and the University of Tokyo has developed a new composite in which three-dimensional nano-interfaces are distributed throughout the material by coating the surfaces of magnetic-insulator powders with a metal and sintering them. Using this structure, the team succeeded in observing thermoelectric conversion driven by spins in an insulator, a phenomenon previously observed only at nanoscale thin-film interfaces, in a macroscale material.
This research was published in Nature Communications.
Thermoelectric conversion, which uses the vast amounts of waste heat and unused heat around us as electrical energy, is one of the key technologies for improving energy-use efficiency and achieving carbon neutrality. The spin Seebeck effect is a physical phenomenon discovered in Japan in 2008 in which applying a temperature gradient to a magnetic material enables thermoelectric conversion via spin currents.
Salt may have helped turn Earth into a frozen world 700 million years ago
Earth may have been pushed deeper into a global deep freeze by something surprisingly ordinary: salt. Around 700 million years ago, Earth entered periods of extreme glaciation known as Snowball Earth, when ice is thought to have spread across much or potentially all of the planet’s surface. Scientists have long known that expanding ice could have helped drive this transition: As bright ice replaces darker ocean water, more sunlight is reflected back into space, causing the planet to cool further and allowing even more ice to form.
Now, Aksel Samuelsberg, from University of Tromsø—The Arctic University of Norway, and colleagues have identified another possible feedback that could have amplified this cooling: salt crystals accumulating on the surface of sea ice. Their modeling suggests that these crystals could have made the frozen surface even more reflective, helping temperatures fall rapidly during the early stages of a Snowball Earth event.
Earth’s Inner Core May Hide a Strange State of Matter
Experiments under extreme conditions suggest that iron hydride can enter a superionic state, allowing hydrogen to move through a solid iron lattice.
Far beneath Earth’s surface, the inner core is squeezed and heated to conditions so extreme that some of its ingredients may behave in an unexpected way. Experiments from researchers at Science Tokyo suggest that iron hydride can enter a superionic state, in which the iron structure stays solid while hydrogen moves through it. The results offer new clues about the composition and behavior of Earth’s deepest interior.
Earth’s inner core consists mostly of iron mixed with a small proportion of lighter elements. Under the immense pressures and temperatures found there, alloys containing elements such as hydrogen, oxygen, and carbon are predicted to become superionic. In this unusual state of matter, iron atoms remain close to fixed positions in the crystal lattice while lighter atoms move through that structure almost like a liquid.
Light reveals internal motion in electron crystals and can trigger their melting
Electrons, particles that carry a negative electric charge, typically move through materials. At low densities and temperatures, however, the electrical repulsion between them can overpower their tendency to move, prompting them to arrange themselves into ordered patterns known as Wigner crystals.
In contrast with ordinary crystals, which consist of atoms arranged in a repeating pattern, Wigner crystals are ordered arrangements of electrons in regular, crystal-like patterns inside a material. These electron crystals are valuable platforms for testing fundamental theories of particle interactions and studying quantum phase transitions. Reliable methods for controlling them could also inform the development of future electronic, optoelectronic, spintronic and quantum devices.
Researchers at the University of Maryland, ETH Zurich and other institutes recently examined a Wigner crystal in a single, atomically thin layer of tungsten diselenide (WSe2), which belongs to a family of materials called transition metal dichalcogenides.
How the sun’s galactic journey and superflare-filled youth shaped Earth’s climate
At the center of our solar system, the sun influences every planet that orbits it. In two recent studies, scientists uncovered how ancient events in the sun’s history may have helped create Earth’s unique climate and driven previously unexplained climatic shifts.
In new research, scientists at NASA’s SHIELD (Solar Wind with Hydrogen Ion charge Exchange and Large-Scale Dynamics) center—one of NASA’s DRIVE (Diversify, Realize, Integrate, Venture, Educate) Science Centers—trace the trajectory of the heliosphere, the massive bubble created by our sun that envelops our solar system, as it moved through our galaxy and influenced Earth’s climate along the way. In another paper, a NASA scientist and co-authors investigate how the younger, dimmer sun managed to heat Earth by seeding the production of potent greenhouse gases.
Scientists Finally Solve a 20-Year Mystery About Diamond Melting
Direct measurements of diamond melting under extreme pressure resolved a long-standing theory-experiment mismatch and could improve both fusion research and planetary models.
Diamond is not only a gemstone. This exceptionally hard form of carbon is also used in the tiny capsules that surround fuel in inertial confinement fusion experiments, and researchers think carbon may form diamonds that fall through the interiors of ice giants such as Neptune and Uranus.
Both environments expose diamond to immense pressure, yet experiments and computer simulations have long produced conflicting descriptions of what happens to the material under such extreme conditions.
Scientists Observe Quantum Heat Waves at Room Temperature For The First Time
We’ve got another notable first in the field of physics to report: A specific type of quantum behavior in waves of heat has now been observed at room temperature, rather than at the ultra-low cryogenic temperatures that are usually required.
The quantum behavior is phonon focusing, which is where atomic-level, heat-carrying vibrations (the quantum packets known as phonons) travel through a non-metallic material in specific patterns, like rays from a star.
Crucially, this is different from the standard behavior of heat-transporting phonons at room temperature, where the heat spreads out evenly in all directions (a classical rather than quantum way of moving).
Consciousness beyond the brain
Most scientists think that consciousness is created by the brain. After all, most assume consciousness vanishes if the brain is destroyed. But what if this consensus view is radically mistaken? Join distinguished Cambridge scientist Rupert Sheldrake as he argues that the mind extends beyond the brain and explores the radical implications of this account.