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Spintronics doesn't use spin
(Fig.1) No progress. Despite extremely longtime researches wasting money, spin wave = quasiparticle magnon has been useless since 1930s
Spin wave expressed as fictional magnon quasiparticle is just a very unstable, ultra-short-lived magnetic fluctuation (= consisting of electron's orbits, Not of unphysical spin ) in magnetic material excited by laser light (= microwave pulse antenna ) under external magnetic field ( this-p.2-4 ).
↑ The unreal electron spin is unmeasurable in all the spin wave experiments that just measure the oscilloscope (= electric current vibration ) or magnetization change as a sign of the fictional spin wave or magnon quasiparticle, which is also detected as the polarization change of light reflected by magnetic material or by using magnetic force microscopes ( this-p.2-right ). ← All of these instruments for spin wave are too bulky to be practical.
Despite extremely long years of fruitless researches (= since 1930s ) and the media-hype, this spin wave (= fictional magnon quasiparticle ) is still useless, with No practical application ( This 3/22/2025 ), which fact proves spin wave or magnon can never be put to practical use.
The 5th paragraph of this overhyped news (2/12/2025) says
"The study opens new frontiers in magnon research and beyond; developments in "ultrafast" imaging techniques, such as this one, are essential to advancing the field of neuromorphic computing, where researchers try to replicate the energy efficiency and parallel processing capabilities of the human brain"
↑ This research paper's abstract says nothing about neuromorphic computing or human brain (= so useless magnon research ), contrary to the above hyped news (= There is a wide discrepancy between overhyped fake news and actual papers )
The 1st paragraph of another overhyped news (5/22/2025) says
"which processes information using magnons (spin waves)... and be applicable in various fields such as next-generation neuromorphic (brain-mimicking) computing structures"
↑ This research paper's abstract also says nothing about any practical use such as hyped neuromorphic computers, contrary to the above hyped news.
↑ This research (= p.2-5) is just about impractical theory with No experiment, and tried to express fictional magnon quasiparticle only as unphysical abstract math symbols with No real particle shape.
The 4th and 2nd-last paragraphs of this overhyped news (5/15/2025) say
"When electrons dance in a coordinated manner, their movements create waves called magnons (= fictional quasiparticle )"
"This could (= just speculation, still useless ) lead to faster data processing, reduced energy consumption and longer battery life for everyday electronics such as smartphones, computers and wearable devices"
↑ This research paper ↓
p.1-abstract-last says "Our experimental findings introduce a strategy for controlling magnons and underscore the need for further theoretical studies to better understand the underlying microscopic interactions between magnons and phonons." ← No mention of any practical use such as smartphone, computers, contrary to the above overhyped fake news.
p.4-left-3rd~4th-paragraphs express fictional magnon quasiparticles only as unphysical math symbols and pseudo-spin model with freely-fitting parameters J with No quantum mechanical prediction.
↑ p.6-Methods just used optical, Raman spectroscopy macroscopically seeing some material by light, X-ray or electron microscope (= to "imagine" fictional magnon quasiparticle ), which has nothing to do with smartphones, computers, longer batteries or fictional magnon quasiparticles, contrary to the above hyped news.
The 4th, 12th paragraph of this overhyped news (6/12/2025) says
"When these spins all move together, they create a wave or "excitation" called a magnon (= fictional quasiparticle )"
" Their approach could (= just speculation ) open new ways of processing information using magnons, with implications for the development of quantum computers" ← false
↑ This research paper ↓
p.1-abstract (or this-abstract ) says nothing about quantum computers, contrary to the above hyped news.
↑ p.2-Fig.1, p.3-Fig.2 ~Fig.3 shows this research just excited some magnetic vibration on some bulky material (= ~mm ) by antenna microwave pulse, and this vibration interference (= fictional magnon quasiparticle ? = undetectable ) was measured by the output (classical) oscilloscope.
↑ So this research has nothing to do with quantum computers, any practical application or fictional magnon quasiparticle (= spin wave ).
The 1st, 3rd, 6th paragraphs of this overhyped news (4/14/2025) say
"A team... opening pathways for revolutionary applications in quantum computing, communication, and sensing"
"The discovery was made in a crystal composed of erbium, iron, and oxygen that was cooled to minus 457 Fahrenheit and exposed to a powerful magnetic field of up to 7 tesla" ← extremely low temperature with No practical application
"the resulting collective excitation is known as a (quasiparticle) magnon."
↑ This-research paper's p.1-abstract says nothing about quantum computers, communication nor sensing contrary to the above hyped news.
This-last-paragraph says
"The ultimate goal, a fully functional magnon computer, has Not yet been achieved."
The 2nd, 5th-paragraphs of this hyped news (2/4/2025) say
"this innovation marks a transformative advance in unconventional computing, with significant potential (= still unrealized ) for next-generation telecommunications, computing, and neuromorphic systems." ← hype
"built a unique experimental setup using 49 individually controlled current loops on an yttrium-iron-garnet (YIG) film. These loops created tunable magnetic fields to control and manipulate magnons."
↑ This above research paper ( this ↓ )
p.3-Fig.1, p.5-Fig.3, p.6-Fig.4 show they applied various controllable electric currents to 49 omega-shaped loops (= each loop is bulky, very big = 1.1mm, = Not a computer, this-p.5 ) to generate various magnetic field, and then input microwave pulses whose transmission (= modified by 49 magnetic field loops ) was measured by output detectors. ← That's all. No computers nor magnon quasiparticles.
↑ p.9-left-last~right says "In this manuscript, we report the realization of only linear functionalities. However, it is important to note that many tasks, such as neuromorphic computing or logic gates, inherently require the nonlinear regime and cannot be achieved in a linear system." ← neuromorphic computing cannot be achieved after all.
↑ This device (= just measuring the excited microwave or magnetic pulse lacking long-term storing memories ) is too big, too bulky (= one omega-shaped magnetic loop is 1.1mm ( this-p.6-left ), which is completely impractical, far bigger than today's practical DRAM compact memory bit of less than 50nm ), which bulky fictional magnon device can never be a practical (neuromorphic) computer.
↑ Actually, the 2nd-last-paragraph of this site about this same bulky magnon device says
"it has several drawbacks, ..The demonstrator is big and consumes a lot of energy"
↑ The fictional spin wave or magnon quasiparticle is useless, bulky, energy-inefficient with No practical application, contrary to a lot of hypes.
The 1st, 3rd-last paragraphs of this hyped news (3/29/2023)
"A magnon corresponds to the specific amount of energy required to change the magnetization of a material via a collective excitation called a spin wave."
"Now that we have shown that spin waves write data by switching the nanomagnets from states 0 to 1, we need to work on a process to switch them back again" ← This spin wave (= magnon quasiparticle ) switch is useless, unable to change 1 bit state back to 0.
↑ This research paper ↓
p.2-Fig.1 shows this magnon bit is impractical, too big (= one magnon bit size is bigger than 25μm, which is much bulkier than today's ordinary memory's bit of less than 50nm ).
p.1-right~p.2 says they applied electromagnetic wave (= VNA ), which causes magnetic vibration (= fictional spin wave or magnon quasiparticle ) under applied magneic field (= H ), which travelled 25μm, and flipped the direction of magnetization of some nanostripes (= bit change 0 → 1 ).
↑ The above research's Reviewer-p.3-#3-last said
"1. The authors emphasize too much on the low power consumption of their devices. The magnetic
fields (= H ) are still needed in the demonstration. They are suggested not to oversell it.
2... However, the size of the devices is still too large"
↑ So this so-called magnon computer's bit is impractical, too bulky (= one bit is more than 25μm ), whose operation needs many bulky instruments such as the electromagnetic wave emitter, the magnetic wave reader, external magnetic field generator and spin wave path (= for each bit )...
↑ This magnetic fluctuation (= spin wave magnon ) is neutral, inconvenient, which can Not be controlled freely nor directed to some specific positions like ordinary memory bits based on electric charges.
↑ Even one bit of (bulky) magnon bit can Not be controlled (= they just randomly flipped the magnetization of some part of the material from 0 to 1, Not from 1 to 0 ), which is completely useless for any technologies such as overhyped neuromorphic computers.
(Fig.2) Very short-lived spin magnetic wave (= lifetime is only nanoseconds = ns ) can propagate only micrometers (= μm ), which is useless for any spintronics devices.
The lifetime of this impractical spin wave (= magnon ) is extremely short (= only nanoseconds, this 2nd-paragraph, this p.8-Fig.8, this p.4-Fig.3d ).
This p.1-left says
"However, the utilisation of magnons (= spin wave ) in magnonic applications can be limited by their
lifetime, which can range from a few tenths of a microsecond down to tens of femtoseconds" ← magnon or spin wave is too short-lived to be practical
This abstract-middle says
"A long-range spin-wave propagation is observed with a decay length of up to (8.0 ± 1.5) μm and a large spin-wave lifetime of up to (44.7 ± 9.1) ns" ← Spin wave is too short-lived (= only 44 ns lifetime ) to be a practical device such as memory.
This extremely short-lived spin wave can propagate only micrometers ( this-abstract, this abstract ) ~ millimeters (= damping ), which are too unstable and too short-lived to be a practical memory or data transfer spintronics device ( this p.3-Table I ).
This p.1-left-1st-paragraph says
"One challenge in spin-wave based applications is the strong spin wave damping such that it can
only propagate a relatively short distance, order of millimetres even for yttrium iron garnets"
This p.2-2nd-paragraph says "SW (= spin wave ) decay length of 50 μm"
Exciting or generating spin wave consumes a lot of energy, which is extremely energy-inefficient. And manipulation and detection of spin wave is also too difficult to be practical.
This p.1-right-2nd-paragraph says "exciting and probing magnons efficiently in 2D ferromagnets remain a challenge"
This p.1-left-2nd-paragraph says
"However, these
spin waves have either short decay lengths or are experimentally very difficult to excite and detect"
As a result, contrary to a lot of hypes (= "promising" spin wave or something ), spin wave or magnon has been deadend for a long time, with No hope of practical application.
To send information, just using ordinary electromagnetic wave traveling faster and longer distance is far better than using the short-lived unstable (fictional) spin wave that needs additional bulky energy-inefficient instruments taking the trouble to convert electromagnetic pulses into the impractical spin wave.
This-p.17(or p.16 )-left-lower~right (or this-p.18 in 2024 ) says
"most of these methods have
drawbacks such as low excitation efficiency, selective excitation wavelengths, complex spin-wave emissions, or unrealistic integration"
"In addition, an integrated magnonic circuit containing multiple logic gates and suitable for further cascading has Not yet been experimentally demonstrated" ← Overhyped magnonic neutromorphic computers are impossible.
"This approach suffers from a large number of required conversions from spin to charge and vice versa, which have been identified as a serious bottleneck, especially due to the relatively low conversion efficiencies achieved"
"However, an efficient on-chip spin-wave amplifier to compensate for the damping loss is still under development "
↑ Spin wave or magnon quasiparticle is useless, energy-inefficient, too unstable to use for some computers.
This-Challenges in magnonics (3/22/2025) says
"One of the primary challenges in magnonic and hybrid quantum systems is the need for high-quality magnonic materials. The efficiency of magnon-based devices heavily depends on low-loss magnetic materials that support coherent spin-wave propagation. Current materials, such as yttrium iron garnet (YIG), offer low damping properties but are difficult to integrate with existing semiconductor technologies"
↑ Despite this hopeless material of yttrium iron garnet (YIG) that proved to be impractical, researchers on fictional spin wave or magnon quasiparticle have continued to use this hopeless YIG in vain for a long time ( this-p.3, this-p.3-Fig.2 ) due to the deadlocked quantum mechanics.
(Fig.3) Physicists just artificially fit parameters to experiments without quantum mechanical calculation nor prediction of fictional spin wave or magnon quasiparticle.
Quantum mechanics unable to describe atoms as real objects has to express this (fictitious) spin wave or magnon quasiparticle as nonphysical math symbols with No concrete shape ( this p.2, this p.9-(55) ).
Furthermore, quantum mechanics cannot predict the behavior of this spin wave, so there is No theoretical evidence of electron spin.
In order to describe this spin wave, physicists have to rely on classical Landau-Lifshitz-Gilbert (= LLG ) equation ( this p.6(or p.3)-1st-paragraph ) with artificially-chosen parameters such as damping parameter α which must be fit to experiments ( this p.11,15, this p.7-left, this p.67(or p.60)-4th-paragraph ) without quantum mechanical prediction.
This p.4-2nd-last-paragraph says
"The damping parameter is
generally set to suit the needs of the experiment. We have used an experimental value for bcc iron and
fcc cobalt as a reference when choosing α"
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