Altermagnets: The first new type of magnet in nearly a century

What altermagnets are (per thread)

• Commenters latch onto the Wikipedia definition: altermagnets have ordered spins like antiferromagnets and zero net magnetisation, but their electronic bands are spin-split in a symmetry-dependent way (not Kramers-degenerate).
• A simplified explanation is offered: neighboring atomic moments cancel so the bulk crystal has no external field, yet internal spin structure still differs between sublattices in a measurable way.
• Others note this is defined for “ideal crystals”; real materials have impurities, but the theory starts from the perfect case.

Explanatory difficulty & popular science criticism

• Several people find the New Scientist diagram and wording confusing or misleading (arrows, colors, “magnetic arrows”, “rotated atoms”).
• There’s frustration with both pop-sci oversimplification and Wikipedia’s dense, jargon-heavy style; some find math/physics pages “indecipherable” unless you’re already in the field.
• A few attempt plain-language rephrasings, while others lean into technobabble jokes (Star Trek, turbo encabulator).

Potential applications discussed

• Main excitement centers on spintronics and data storage: a material that responds to spin but has no macroscopic field could allow extremely dense, interference-free magnetic bits.
• One commenter imagines bits read by a “light” pulse and flipped by a “strong” pulse, with long retention and high endurance, possibly CMOS-compatible.
• Others suggest improved Hall-effect or related magnetic sensors and, more speculatively, non-volatile memory closer to “core” semantics (state preserved when power is off).

Technical limitations & skepticism

• A researcher in the area notes that reading information in a zero-net-magnetisation state is hard; conventional read heads rely on stray fields. Practical readout may require bulky or invasive methods.
• Another cites the article’s own caveat: current ways to realize altermagnets (strain, complex layer stacks) are hard to scale.
• Comparisons are made to previous “revolutionary” memory tech (3D XPoint) that failed mainly on cost and market fit, not physics. People doubt this will beat flash/HDD/tape on price per bit soon.
• Some see the “new type of magnetism / new state of matter” framing as classic clickbait; they expect scientific value but modest near-term impact.

Meta: peer review, funding, and credit

• Long subthread debates whether arXiv vs journal publication should be labeled “peer reviewed,” with strong criticism of current gatekeeping, incentives, and paywalled journals.
• Others defend peer review as an imperfect but useful signal.
• Funding is noted as largely public (Czech, German, EU agencies), prompting side discussion about which countries best convert state-funded tech/IP into citizen benefit.
• A reader finds it odd that the article names some researchers but not others (e.g., a Chinese group), seeing it as a credit issue.