spintronics

Every oscillator carries its own compass, built into the crystal lattice. Until now, spin Hall nano-oscillators, tiny microwave sources driven by spin current, could not do without an external magnet: it was the magnet that set the common axis around which the magnetization oscillated.

Two dancers on one stage: one pulls the partner in one direction, the other in the opposite. In the crystal Cu2(OH)3Br, known as botallackite, copper atoms form chains where the spins (magnetic moments) of neighboring ions align either parallel, as in a ferromagnet, or antiparallel, as in an antiferromagnet.

A door lock with two different keys: one turns easily, the other demands noticeable effort. That is how two layers of hexagonal boron nitride behave when twisted relative to each other. This material consists of boron and nitrogen atoms arranged in a hexagonal lattice, and its layers can sit in different registries, like two identical grids shifted by different angles.

In some crystals, electrons are not spread uniformly but arrange themselves into a strict checkerboard: one cell has more electrons, the neighboring cell has fewer. Such a pattern is called charge order, and for a long time it was considered something frozen, like a pattern on frosty glass.

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.

The crystal is like a city with different streets: on some, cars drive fast and far, on others, they crawl and get stuck. In the layered material CrPS₄, magnetic waves that carry spin (a particle's intrinsic angular momentum) behave the same way.

Two sheets of graphene — the thinnest layers of carbon, just one atom thick — are stacked like bread in a sandwich. Between them lies a magnetized layer of CrSBr. When current flows through this sandwich, the resistance depends on which way the magnetic moments in the middle layer point.

In an ultracold cloud of atoms cooled to near absolute zero, regions with different spin orientations emerge, like patches with different magnetization. The boundaries between them are called domain walls. Usually they are stationary, but in this experiment the walls started moving on their own.

A lone erbium atom sits on a silver substrate, and its spin, the electron's internal rotation, stores quantum information. Previously, flipping this spin required a magnetic pulse: a blunt tool that disturbs neighbors and works slowly. Now physicists from Germany and Korea have shown that a single electric voltage suffices.

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.

Ordinary electric current heats up wires — anyone who has touched a phone charger knows that. But there's another kind of current: instead of electrons rushing in a crowd in one direction, they spin in sync, like figure skaters in a pairs routine. This coordinated rotation is called a spin current, and it produces almost no heat.

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.

A parquet floor where every other plank is turned the opposite way looks symmetric. But if you run your hand over it, in one direction your fingers glide along the grain, and in the other they catch. That's roughly how the new type of magnetism studied in the crystal AgCrP2S6 works.

The book is open to the middle. Current runs along the spine, while the pages remain cool. That's roughly how a two-dimensional topological insulator works — a material where electricity flows only along the edges, while the interior stays still.

Some materials are internally like a Möbius strip: their electronic states are twisted in a special way. Such topological properties are usually manipulated with a powerful magnetic field, as if trying to flatten the strip with a sledgehammer. A group of researchers has found a more delicate tool.

In some crystals, the magnetic moments of atoms oscillate in sync, like a wave in a stadium. It carries spin without charge current, without heating the material. This flow resembles an invisible river — silent and cold. Two-dimensional altermagnets are special materials: spin waves in them run differently along different axes.

A quantum computer is like an orchestra where each musician, a qubit, must play their part accurately and on time. Usually, musicians are seated in fixed positions and connected by conductors' consoles. But what if we let them move freely across the stage and turn the movement itself into part of the music?

Any measuring device is spoiled by quantum noise — the chaotic jitters of elementary particles. To tame it, physicists used a trick on calcium fluoride molecules, much like squeezing a balloon: press in one spot, and it bulges in another.

A quantum particle traveling around a closed ring leaves two distinct 'records' along its path. The first is like a fingerprint on a doorknob: it remains unchanged no matter how many times you turn the knob, and it only tells you about the shape and material.

Run a current through a spring of organic molecules, and the electrons that come out are almost all spinning the same way. This trick is called chiral spin selectivity, and it has long puzzled physicists. In light atoms, spin (the particle's intrinsic rotation) is too weakly coupled to charge motion to achieve nearly perfect sorting.

A rubber band stretches and snaps back. A steel spring compresses and expands. Elasticity seems like a property of simple things — a piece of metal or a drop of gel. But the authors of this work looked deeper. They showed that the electron's spin, its own tiny rotation, can also be elastic.

A comb rubbed through your hair picks up scraps of paper. Physicists decided to apply this simple trick at the microscopic level — to control magnetic vortices called skyrmions. A skyrmion is like a tiny tornado in a sea of magnetization: at its center, compass arrows point up, while at the edges they twist downward.

A magnetic vortex, or skyrmion, is like a tiny whirlpool in the sea of spins — the atoms' intrinsic magnetic moments. Like a whirlpool in a river, it twists the magnetization around itself, and this pattern is remarkably robust: hard to destroy with a random jolt.

In a piece of ordinary magnet, all electron spins, tiny magnetic arrows, point in the same direction. It's a formation of soldiers facing their commander. This order is called a collinear altermagnet.

In a tiny magnet, information is encoded not in which way the arrow points, but in how the directions of its atoms alternate. In antiferromagnets, these arrows cancel each other out, so the material appears non-magnetic from the outside. The data is there, but you can't read it the usual way: the state is like a note written in invisible ink.

Among magnets, there are quiet masters of disguise. An ordinary magnet attracts paperclips and has two poles — north and south. But there are materials that are internally arranged like a magnetic chessboard: their atoms are aligned in a strict order, yet externally the material behaves neutrally, as if no magnet exists at all. Such substances are called altermagnets.

Two superconducting banks are connected by a bridge of magnetic material. Inside the bridge lies a domain wall: a narrow boundary where the magnetization rotates, like a column of soldiers changing their marching direction.

In a thin nickel oxide film, magnetic regions are arranged in strict order like mosaic pieces. A single laser pulse instantly heats the material, and the mosaic falls apart: domains lose their orientation and mix.

A rug lies flat, but if you push it from the edge, wrinkles run across it. In a thin film of tantalum sulfide (1T-TaS2), wrinkles made of electrons, charge waves, freeze as if the rug were stuck to the floor. To move them, you need to apply force. Scientists have found a way to control this force using an electric field and a magnet.

Usually, current in a metal acts like boiling water on ice: it heats the material and destroys magnetic order. But in a layered structure of tungsten ditelluride and the ferromagnet Fe3GeTe2, current behaves differently.

In a thin layer of liquid crystal (a substance that flows like a liquid but has molecules arranged in order, as in a solid) vortices smaller than the thickness of a human hair are born. These vortices resemble tiny spinning tops: they can move without breaking apart and behave almost like real particles.

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.

Inside a magnet, there are regions where all the atomic magnets point in the same direction. Between such regions lies a narrow transition zone where the magnetization direction gradually rotates. This zone is called a domain wall. Previously, it was considered massless: give it a push, and it stops immediately.

A chunk of nuclear fuel inside a reactor is not just a solid. When heated, the uranium atoms in it start to 'wiggle' their magnetic moments, and this motion changes thermal conductivity and other properties.

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.

A bacterium in a drop of water is looking for food. Around it, there's a chemical gradient: more food molecules on one side, fewer on the other. How should it move to reach the tasty spot fastest? It could steer smoothly, like a cyclist dodging a puddle. Or, like a bacterium, it could periodically stop, tumble, and swim off in a random direction.

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.

Every electron is like a spinning top: it twirls around its own axis. This rotation is called spin. In conventional electronics, we don't use spin — only charge. But that's a missed opportunity: if we learn to control spin, chips could become faster and more efficient.

Light in semiconductors is born from pairs of charges, an electron and a hole, that attract each other like a magnet to a fridge. Such a pair is called an exciton. If you add one more charge to the pair, you get a trion — a trio of three particles.