spin wave

A room of funhouse mirrors: you stand in the center, and the echo of your voice comes back from an unexpected direction, amplified and distorted. That is how spin waves in a thin magnetic film, excited by an antenna, reflect off defects and irregularities, creating a tangled pattern of fields.

In a thin film of cobalt and iron deposited on a silicon substrate, a tiny magnetic vortex twists into existence.

A magnetic vortex is like a tiny whirlpool in the sea, except that instead of water, it's magnetization that swirls. Such vortices could become memory cells in future computers, but to write and read information, you need to be able to move each vortex individually. So far, this is done crudely — shifting a whole bunch at once.

A quantum wire is like a high-speed highway where electrons race in a dense stream. Each electron has its own rotation, spin, and until now it was thought that splitting this stream into two lanes, for 'left' and 'right' rotation, without losing quantum order was nearly impossible. You'd need either strong magnets or complex tricks that waste energy.

In the first fractions of a second after the Big Bang, the universe was a stage of rapid change. A stretched rubber sheet that cools quickly becomes covered with microscopic cracks. A similar process on a cosmic scale could have given rise to cosmic strings — ultra-thin but super-dense threads of energy stretching across the entire universe. These strings are not just defects in space.

In the first 10⁻³⁵ seconds after the big bang, the most rapid part unfolded. Space expanded faster than light — that's expansion of the universe (inflation). Almost the entire score was performed by a single field, the inflaton, conducting the tempo and key.

A stone falls into still water, and smooth rings spread across the surface. If the stone doesn't just fall but also spins, tiny whirlpools, vortices, appear on the surface. Light can do the same, only instead of water, it's space and time themselves.

A spinning top that makes a hundred turns per second suddenly starts losing speed dramatically — much faster than any known top. That's exactly what pulsar J0435+3233 is doing. It's a dead star, crushed to the size of a city, but whirling at a furious rate.

Every atom in a magnet is like a tiny compass needle. These needles can point in different directions, and their collective dance determines the material's properties. But calculating this dance directly, atom by atom, is a task too heavy even for supercomputers. The new model, named STEP, takes on the role of a conductor.

In a crystal that for centuries was called 'fool's gold,' physicists have spotted genuine treasure. The compound MnTe2 with a pyrite structure has become the stage for a quantum ballet: spin waves here twist into left- and right-handed vortices, with the twist direction firmly tied to momentum.

Quantum technology urgently needs a universal 'translator' between the languages of microwaves and light. Superconducting qubits communicate on centimeter wavelengths, while photons in optical fiber talk at optical frequencies.

A crowd is trapped in a narrow corridor between two rows of mirrors. Every now and then, someone shoves the wall hard, and a rumble rolls down the corridor — similarly, in the plasma of galaxy clusters, whistler waves and ion-cyclotron waves appear.

A giant drum has just taken a hit. Its membrane is still trembling, but besides the main boom, a fine ripple spreads across it — someone ran a finger over the taut skin. In much the same way, in the first moments after the Big Bang, spacetime vibrated not only with the "roar" of expansion but also with the tension of suddenly emerging magnetic fields.

The La3Ni2O7 crystal resembles a layered pie, where the filling of nickel and oxygen atoms alternates with lanthanum layers. At ambient pressure, it does not conduct without resistance, but squeeze it or grow it as a thin film, and high-temperature superconductivity emerges.

In an ordinary crystal, atoms stand in neat rows like soldiers on a parade ground. Any deviation from this formation is usually considered harmful: disorder scatters waves and quickly dampens collective motions of particles.

A small ball with an iron core lies on a surface while a magnetic field spins around it. The ball starts rolling like a wheel and usually goes in the direction the field rotates. But sometimes it suddenly turns around and rolls the other way — against the field.

An electron in an ordinary wire is like a courier carrying both a package and the recipient's signature at once: its charge and spin are always together. But if the wire is made just one atom thick, the courier gets cramped. In such a one-dimensional tube, electrons cannot overtake each other, and their collective behavior changes beyond recognition.

A crystal is like a city where houses stand in neat rows. But if you slightly stretch the ground beneath the city, the houses may tilt, and the tilt can ripple as a wave from block to block. In SrTiO3 and SrMnO3 crystals, scientists have found exactly such a hidden mode: a soft wave of tilting oxygen octahedra that had gone unnoticed before.

In most magnetic materials, a domain wall, the boundary between regions with different magnetization, moves in one direction under current, set by the current's direction. But in ferrimagnets near a special point where the angular momenta of two sublattices cancel each other, the behavior changes.

Cilia are tiny hairs on cell surfaces. They beat like oars, moving fluid. In the lungs, they push dust and microbes out. But their lengths vary: in humans, they are thousandths of a millimeter; in comb jellies, several millimeters. How do such different cilia work together? Scientists built a machine that jerks fluid sharply, as if a cilium had struck. They filmed it with a high-speed camera.

If you compress a plate with accordion-like cells, a kink wave runs through it, like a wrinkle in a rug when you push it with your foot. Such waves can switch the material between two stable shapes, and this is the basis of mechanical memory. But if a table leg gets in the way of the wrinkle, it gets stuck. In a new study, researchers showed how to nudge it loose without brute force.

In an ordinary wire, heat drives electrons: that's the Seebeck effect, familiar from thermocouples. But in magnets, things are trickier: charge carriers also carry spin, their own little 'top.' In some materials, called altermagnets, electrons with different spins interact differently with the crystal lattice, so a…

If you toss a stone into a pond, ripples spread across the water. Tiny magnetic crystals also host waves — except it's not water that oscillates but the direction of magnetization. These are called spin waves. They travel through the crystal like ripples on a surface and can carry information.

An ordinary solar cell does one thing: when the sun shines, current flows. Here, when the sun shines, the current flows differently depending on which side you bring the magnet.

In an ultracold cloud, potassium atoms behave like waves that can add up and amplify each other — much like sound waves in a musical instrument create a loud chord. Physicists have learned to control this process by tuning the strength of atomic interactions with a magnetic field.

The popping lid of a jam jar is the hero of this story. Press it, and with a loud click it flips from a convex to a concave shape. Exactly the same happens with a hinged beam inside each cell of a new mechanical lattice. Scientists assembled these snapping beams into a hexagonal grid, like honeycomb, but made of elastic plates. When one beam is sharply compressed, it snaps and pushes its neighbor.

A crowd of people in a subway station moves slower than individuals: everyone gets in everyone else's way. A similar picture emerges in a dense cloud of magnetic atoms exchanging energy. Previously, it was thought that the transfer rate depended only on the atoms' own properties.

Waves in magnets resemble the vibrations of a string: if you pluck a string, it sounds a single note, but with a strong pluck, overtones appear — sounds at multiple frequencies.

Right after its birth, the Universe wasn't just expanding: it was inflating at an unimaginable pace. This stage, called inflation, was proposed by Alan Guth. New models compare the process to inflating a balloon with quick, jerky pumps.

A sugar solution can twist light — many have seen this in polarization experiments. Surprisingly, a similar trick appears in the fabric of the cosmos itself.

A conductor leads an orchestra of billions of musicians while still hearing each one individually. That's roughly the challenge physicists face when trying to make light and electron spins in solids work together.

Every hour, when the hands of a clock align at twelve, something happens in Earth's magnetosphere. It's as if an invisible conductor raises a baton, and waves race along magnetic field lines toward the surface. They're called pearls: on recordings, they look like a string of beads strung along time.