8 ms·

Superconductivity near room temperature

164 points by Elof 7y ago

ttsda 7y ago
At pressures a million times those experienced on earth. Still an advance, of course.
- saagarjha 7y ago
  Also, the temperature (250 K, -23°C) is a bit chilly to be called “room temperature”. Still, this means you don’t need liquid nitrogen for cooling: a good but standard refrigeration system would be enough (and their insane diamond pressure apparatus, of course).
  - maxxxxx 7y ago
    Isn’t nitrogen cooling much easier to achieve than this level of pressure?
    - hackerpacker 7y ago
      well the pressure aspect wouldn't require constant energy input. And I assume it is a lot more economical to use a consumer refrigerator than liquid nitrogen. But yah, you can bathe a much more complicated "circuit" in liquid nitrogen a lot easier than compressing it with diamond anvils. Though no commercial superconducting computers have emerged, cmos is just too cost effective currently, and the known examples are still in the 4K range.
      - sfasfsafd 7y ago
        "well the pressure aspect wouldn't require constant energy input." But you have to put energy in to compress it, energy that is lost (since you're compressing it isothermally). Since we're talking about 1E6 atm, any appreciable volume would require insane amounts of E to compress.
        maxxxxx 7y ago
        Wouldn't that also be pretty much a bomb if the pressure got relieved? I don't know how to do the math but 1E6 atm seems a lot of energy (is it potential energy?) that has to go somewhere.
        bzbarsky 7y ago
        TL;DR: It's pretty much like a bomb, yes. How much energy it is depends on the volume change as you compress. If your material is completely incompressible, there is no volume change, no work done as the pressure rises, and therefore no energy stored. In practice, for a material of bulk modulus K by definition you have -K dV/V = dP. as the basic differential equation relating pressure and volume (if we assume that the bulk modulus is constant through our pressure range, which is quite an assumption in this case). Solving that, we get: V = V_0/exp(P/K) where V_0 is the original volume and V is the volume after the pressure has been applied. Bulk modulus is commonly measured in GPa, so we're going to do that here. 1atm is about 1e5 Pa or 1e-4 GPa. The work done while compressing is the integral of -PdV, which per that first differential equation we can rewrite as the integral of P * V/K * dP (we want to integrate dP because we know what the limits are: it's going from 1atm, or 1e-4 GPa, to 1e6 atm = 1e2 GPa). Plugging in our expression for V we get the integral, from 1e-4 to 100, of P/K * V_0/exp(P/K) dP. The integral there is: K * V_0 * (-P/K - 1) * exp(-P/K) For simplicity, I'm going to approximate that 1e-4 by 0, so we get: K * V_0 * ((-100/K - 1) * exp(-100/K) + 1) when we evaluate at the two endpoints. OK, so let's try an actual material and actual volume. Steel has a bulk modulus of 160 GPa according to <https://en.wikipedia.org/wiki/Bulk_modulus#Selected_values> https://en.wikipedia.org/wiki/Bulk_modulus#Selected_values>. So for steel we have: 160 * V_0 * ((-100/160 - 1) * exp(-100/160) + 1) = 160 * V_0 * 0.13 = 21 * V_0 or so. If we assume we started with a 1 cm^3 volume of steel, that's an energy of: 21e9 N/m^2 * 1e-6 m^3 = 2.1e4 J or about equivalent to 5 grams of TNT per <https://en.wikipedia.org/wiki/TNT_equivalent> https://en.wikipedia.org/wiki/TNT_equivalent>. For comparison, 1 cm^3 of steel is about 7-8 grams of material, so we're right in the "about as much energy as the same weight of TNT" ballpark. Obviously if you start with a larger volume you end up with more stored energy: if we started with 1m^3 we end up equivalent to about 5 tons of TNT. If your material is more compressible, the numbers are higher, as long as it's not too compressible (in which case it just collapses into a tiny volume quickly and not much more work gets done after that). If we take K = 50 (a typical number for glass from that table), you get: 50 * V_0 * ((-100/50 - 1)*exp(-100/50) + 1) = 50 * V_0 * 0.6 = 30 * V_0 If your material is less compressible, you store less energy; for diamond with K = 443, you get something like 9.7*V_0. Again, all this assumes pressure-invariant bulk modulus, which seems moderately unlikely when you are dealing with pressures that are on the order of the size of the bulk modulus or even larger, as here.
      - contravariant 7y ago
        I'm not entirely sure but I think there are no theoretical obstructions to maintaining a ridiculously high pressure indefinitely. Although I suppose there aren't any theoretical obstructions to indefinitely maintaining low temperatures either.
        imtringued 7y ago
        Even blackholes lose their mass through radiation. Nothing can maintain a high pressure indefinitely.
- skunkworker 7y ago
  This. lanthanum hydride @ 250K at > 1 million atm. It's still very impressive though.
- Zanni 7y ago
  Nobody wants "high temperature" superconductors. They want superconductors at roughly standard temperature and pressure. This is only an advance by the extremely artificial metric of considering temperature only. Ceramic superconductors work at liquid nitrogen temperatures and standard pressure, which is much more accessible. I'm not raging at ttsda. It is an advance. Of sorts. But not nearly as much as the headline suggests.
  - hoseja 7y ago
    I thought "high temperature", when talking about superconductors, basically means any temperature above the boiling point of nitrogen...
    - chaboud 7y ago
      I think you may mean below. Basically, low temperature superconductors (e.g. niobium titanium) are liquid helium cooled. High temperature superconductors (e.g. YBCO, BSCCO) are everything else, but generally liquid nitrogen cooled.
  - jeffwass 7y ago
    The headline is accurate. In the scientific community, High-Tc superconductors typically refer to Type II superconductors, eg cuprates. And the “High-Tc” term means above temperatures relative to the usual elemental superconductor Tc’s, eg about 20K or so. Materials that can superconduct above 77K are especially sought after since they can be cooled with only liquid nitrogen, much cheaper and abundant than liquid helium.
  - gaze 7y ago
    You’re vastly underestimating what the significance of what this is part of. High Tc superconductivity was thought to be essentially dead. Extremely few significant new results for decades. Now this and magic angle twisted graphene and some other stuff. It’s really really cool. It’s like we’re watching an entire field thawing and lurching forward.
    - 7y ago
- baq 7y ago
  this made me think, is the earth core a superconductor?
  - effie 7y ago
    Interesting idea. It would help to explain persistence of Earth's magnetic field.
  - MichaelApproved 7y ago
    No. The core has pressure but it's way too hot to achieve super conductivity.
- taneq 7y ago
  Technically correct. The most annoying kind of correct.
bhaak 7y ago
> From a scientific standpoint, these results suggest that we might be entering a transition from discovering superconductors by empirical rules, intuition or luck to being guided by concrete theoretical predictions. That would be an exciting development.
PuffinBlue 7y ago
The interesting thing about this is that the work neatly fitted with existing theory: > Drozdov et al. observed this isotope effect and found that, compared with the lanthanum hydride samples, the critical temperature in lanthanum deuteride samples is lower by almost exactly the amount predicted by the theory. So like the article points out: > From a scientific standpoint, these results suggest that we might be entering a transition from discovering superconductors by empirical rules, intuition or luck to being guided by concrete theoretical predictions. Whilst this result might require huge pressures, steady progress towards a theory of super-conduction is an exciting thing indeed.
- tigershark 7y ago
  Also it may open the road to find metastable material at room temperature, although I don’t think that it’s the case for lantanium hydride.
- djaque 7y ago
  I wouldn't be too optimistic. The theory they are talking about is BCS theory. Most of the other high TC superconductors cannot be explained with it and high TC BCS superconductivity so far requires crazy environments with no clear path to making them easier to use. With the kinds of pressures required to make this happen, it's probably easier to just buy liquid nitrogen and use other materials.
stevespang 7y ago
At pressures of more than one million times Earth’s atmospheric pressure ? Totally academic, no real application in real world problems.
chiefalchemist 7y ago
> "Materials known as superconductors transmit electrical energy with 100% efficiency." What is the level of (in)efficieny for say power lines? And power cords, etc around the office/house? That is, of the electricity produced, how much is lost due to how it's transported? Does decentralizing production (e.g., solar panels on your own roof) help in any way?
- krageon 7y ago
  I'm normally not a fan of responding like this, but here goes: If you really do not know these things that is of course perfectly acceptable, but if they truly interested you you could very easily find the information about this out there. After all, it is knowledge you get in any highschool curriculum that even smells faintly of technical information. Given that you do not yet have this (as you miss other, related knowledge), giving you a good response that doesn't involve a lot of theory is very hard. Certainly a response that makes you aware of the nuances in this subject would involve some study. If that does not scare you, I invite you to take a look at a place like this: https://www.khanacademy.org/science/electrical-engineering/ee-electrostatics/ee-fields-potential-voltage/a/ee-electric-potential-voltage https://www.khanacademy.org/science/electrical-engineering/e... and study some of the source material.
  - jacquesm 7y ago
    There is no such thing as a dumb question and if there is one thing that I love about HN it is that people will take the time to answer questions.
    - chiefalchemist 7y ago
      Not only will people answer, it's answers from people who actually know (and are willing to share).
  - amirhirsch 7y ago
    This isn’t a good answer. On average in the US we lose 7% of power in transmission and 8% in power conversion. I pulled these numbers out of thin air, but it’s probably accurate to within a factor of 2 for wherever you are. A home solar power system might mean 7% lost in dc to ac and then you still lose 8% for conversion so basically 5-20% of all the power you produce is lost before it reaches its destination. A more didactic answer might start with defining power, P=IV (power equals current times voltage) and “ohm’s law” V=IR (voltage equals current times resistance) and suggest this means that the power lost to the resistance of transmission line with resistance R is P=I^2R. Since the current you send is proportion to the voltage (One megawatt can be 1Amp at 1000000 Volts or 1000Amp at 1000 Volts, you want to use as high voltage as possible when transmitting long distances. The limiting factor on voltage is the amount of insulation required. Usually power transmission uses three-phase alternating current, which sends power by varying the voltage on three lines each 120 degrees (1/3 period) offset from one another. It’s reasonable homework to read about why AC is better for transmission and also how three phase AC works and determine the economic value of laying three cables instead of two, with variables for the cost of wire, fixed costs per mile, and cost of electricity. ~50% of transmitted power is used to drive three-phase synchronous AC motors. Resistance is related to the resistivity (denoted with a Greek rho) of the material and the cross-sectional area (denoted A) and length (L) of the wire: R=rhoL/A Resistivity is a fundamental property of materials and is related to the free movement of the outer shell of electrons of atoms in a crystal lattice. Superconductors do not have resistance and can carry an extremely large current as a result. Unfortunately superconductors have a maximum magnetic field capacity and require extremely low temperatures requiring cooling with liquid helium or nitrogen.
oh_teh_meows 7y ago
I understand that the achievement in question was made in a high pressure environment; but if we get room temperature superconductors (at standard atm pressure), does that mean large scale hover cars/boards deployment will be viable as well [0]? [0] https://youtu.be/PXHczjOg06w https://youtu.be/PXHczjOg06w
- wolfram74 7y ago
  Room temperature super conductors are in the category of materials that will cause semi-magical transformations in society along side generation techniques that make .001$/KwH electricity, 1$/kwh electricity storage, or >200 gigaPa tensile strength materials for cheap.
- adrianN 7y ago
  It depends on how much it costs.
trebligdivad 7y ago
What's the highest pressure that can be achieved over a useful (1 meter?) distance? I find it amazing that they managed to scale up cryostats to 1km for superconducting powercables at low temperatures - it would just be interesting if they started scaling up high pressure environments.
acd 7y ago
Is the Sun a superconductor? The Sun consist of a high percentage of hydrogen ~73% and there must be really high pressure at the center. The suns central pressure is 2.5*10^11 bar according to nasa. https://en.m.wikipedia.org/wiki/Sun https://en.m.wikipedia.org/wiki/Sun https://nssdc.gsfc.nasa.gov/planetary/factsheet/sunfact.html https://nssdc.gsfc.nasa.gov/planetary/factsheet/sunfact.html
- skykooler 7y ago
  The sun is also at a temperature of millions of degrees. At these temperatures, there is no such thing as chemical bonds, and so the rules with hydrogen from the article don't apply.
  - deleted 7y ago
    [deleted]
  - agumonkey 7y ago
    interesting, is this a sub-field of physics ? high temperature physics or something ?
    - orbifold 7y ago
      Plasma physics I guess, plus magneto hydrodynamics, plus GR for really heavy stars.
      - agumonkey 7y ago
        dank u
    - pmalynin 7y ago
      High energy physics, yes.
      - agumonkey 7y ago
        danke schon
gwbas1c 7y ago
> lanthanum hydride compounds become superconducting at 250 K That's about -10F, or -23C. (And it would make a lot more sense to put that in the article. Most of us don't "think" in Kelvin.)
- penagwin 7y ago
  Oh thanks! Especially since the article says room temperature. I know a lot of people on HN are interested in superconductors but don't necessarily use K frequently if ever.
- alkonaut 7y ago
  That’s regular outdoor temperature in a lot of places. I wonder if there is any type of tech that is used in cold climates (or more on cold days) that would benefit from superconductors so they become more efficient when it’s most needed? Oh - it has to be at 1atm and -20 of course...
- nine_k 7y ago
  It's easy: "room temperature" is about 300K.
apo 7y ago
> Writing in Nature, Drozdov et al.1 report several key results that confirm that, when compressed to pressures of more than one million times Earth’s atmospheric pressure, lanthanum hydride compounds become superconducting at 250 K — a higher temperature than for any other known material. One million atmospheres is an important detail to leave out of the title.
yo1 7y ago
Has this been discussed here? Navy files for patent on room-temperature superconductor. https://phys.org/news/2019-02-navy-patent-room-temperature-superconductor.html https://phys.org/news/2019-02-navy-patent-room-temperature-s... "The application claims that a room-temperature superconductor can be built using a wire with an insulator core and an aluminum PZT (lead zirconate titanate) coating deposited by vacuum evaporation with a thickness of the London penetration depth and polarized after deposition. An electromagnetic coil is circumferentially positioned around the coating such that when the coil is activated with a pulsed current, a non-linear vibration is induced, enabling room temperature superconductivity. "This concept enables the transmission of electrical power without any losses and exhibits optimal thermal management (no heat dissipation)," according to the patent document, "which leads to the design and development of novel energy generation and harvesting devices with enormous benefits to civilization.""

164 points by Elof 7y ago

ttsda 7y ago

At pressures a million times those experienced on earth. Still an advance, of course.

saagarjha 7y ago
Also, the temperature (250 K, -23°C) is a bit chilly to be called “room temperature”. Still, this means you don’t need liquid nitrogen for cooling: a good but standard refrigeration system would be enough (and their insane diamond pressure apparatus, of course).
- maxxxxx 7y ago
  Isn’t nitrogen cooling much easier to achieve than this level of pressure?
  - hackerpacker 7y ago
    well the pressure aspect wouldn't require constant energy input. And I assume it is a lot more economical to use a consumer refrigerator than liquid nitrogen. But yah, you can bathe a much more complicated "circuit" in liquid nitrogen a lot easier than compressing it with diamond anvils. Though no commercial superconducting computers have emerged, cmos is just too cost effective currently, and the known examples are still in the 4K range.
    - sfasfsafd 7y ago
      "well the pressure aspect wouldn't require constant energy input." But you have to put energy in to compress it, energy that is lost (since you're compressing it isothermally). Since we're talking about 1E6 atm, any appreciable volume would require insane amounts of E to compress.
      - maxxxxx 7y ago
        Wouldn't that also be pretty much a bomb if the pressure got relieved? I don't know how to do the math but 1E6 atm seems a lot of energy (is it potential energy?) that has to go somewhere.
        bzbarsky 7y ago
        TL;DR: It's pretty much like a bomb, yes. How much energy it is depends on the volume change as you compress. If your material is completely incompressible, there is no volume change, no work done as the pressure rises, and therefore no energy stored. In practice, for a material of bulk modulus K by definition you have -K dV/V = dP. as the basic differential equation relating pressure and volume (if we assume that the bulk modulus is constant through our pressure range, which is quite an assumption in this case). Solving that, we get: V = V_0/exp(P/K) where V_0 is the original volume and V is the volume after the pressure has been applied. Bulk modulus is commonly measured in GPa, so we're going to do that here. 1atm is about 1e5 Pa or 1e-4 GPa. The work done while compressing is the integral of -PdV, which per that first differential equation we can rewrite as the integral of P * V/K * dP (we want to integrate dP because we know what the limits are: it's going from 1atm, or 1e-4 GPa, to 1e6 atm = 1e2 GPa). Plugging in our expression for V we get the integral, from 1e-4 to 100, of P/K * V_0/exp(P/K) dP. The integral there is: K * V_0 * (-P/K - 1) * exp(-P/K) For simplicity, I'm going to approximate that 1e-4 by 0, so we get: K * V_0 * ((-100/K - 1) * exp(-100/K) + 1) when we evaluate at the two endpoints. OK, so let's try an actual material and actual volume. Steel has a bulk modulus of 160 GPa according to <https://en.wikipedia.org/wiki/Bulk_modulus#Selected_values> https://en.wikipedia.org/wiki/Bulk_modulus#Selected_values>. So for steel we have: 160 * V_0 * ((-100/160 - 1) * exp(-100/160) + 1) = 160 * V_0 * 0.13 = 21 * V_0 or so. If we assume we started with a 1 cm^3 volume of steel, that's an energy of: 21e9 N/m^2 * 1e-6 m^3 = 2.1e4 J or about equivalent to 5 grams of TNT per <https://en.wikipedia.org/wiki/TNT_equivalent> https://en.wikipedia.org/wiki/TNT_equivalent>. For comparison, 1 cm^3 of steel is about 7-8 grams of material, so we're right in the "about as much energy as the same weight of TNT" ballpark. Obviously if you start with a larger volume you end up with more stored energy: if we started with 1m^3 we end up equivalent to about 5 tons of TNT. If your material is more compressible, the numbers are higher, as long as it's not too compressible (in which case it just collapses into a tiny volume quickly and not much more work gets done after that). If we take K = 50 (a typical number for glass from that table), you get: 50 * V_0 * ((-100/50 - 1)*exp(-100/50) + 1) = 50 * V_0 * 0.6 = 30 * V_0 If your material is less compressible, you store less energy; for diamond with K = 443, you get something like 9.7*V_0. Again, all this assumes pressure-invariant bulk modulus, which seems moderately unlikely when you are dealing with pressures that are on the order of the size of the bulk modulus or even larger, as here.
    - contravariant 7y ago
      I'm not entirely sure but I think there are no theoretical obstructions to maintaining a ridiculously high pressure indefinitely. Although I suppose there aren't any theoretical obstructions to indefinitely maintaining low temperatures either.
      - imtringued 7y ago
        Even blackholes lose their mass through radiation. Nothing can maintain a high pressure indefinitely.
skunkworker 7y ago
This. lanthanum hydride @ 250K at > 1 million atm. It's still very impressive though.
Zanni 7y ago
Nobody wants "high temperature" superconductors. They want superconductors at roughly standard temperature and pressure. This is only an advance by the extremely artificial metric of considering temperature only. Ceramic superconductors work at liquid nitrogen temperatures and standard pressure, which is much more accessible. I'm not raging at ttsda. It is an advance. Of sorts. But not nearly as much as the headline suggests.
- hoseja 7y ago
  I thought "high temperature", when talking about superconductors, basically means any temperature above the boiling point of nitrogen...
  - chaboud 7y ago
    I think you may mean below. Basically, low temperature superconductors (e.g. niobium titanium) are liquid helium cooled. High temperature superconductors (e.g. YBCO, BSCCO) are everything else, but generally liquid nitrogen cooled.
- jeffwass 7y ago
  The headline is accurate. In the scientific community, High-Tc superconductors typically refer to Type II superconductors, eg cuprates. And the “High-Tc” term means above temperatures relative to the usual elemental superconductor Tc’s, eg about 20K or so. Materials that can superconduct above 77K are especially sought after since they can be cooled with only liquid nitrogen, much cheaper and abundant than liquid helium.
- gaze 7y ago
  You’re vastly underestimating what the significance of what this is part of. High Tc superconductivity was thought to be essentially dead. Extremely few significant new results for decades. Now this and magic angle twisted graphene and some other stuff. It’s really really cool. It’s like we’re watching an entire field thawing and lurching forward.
  - 7y ago
baq 7y ago
this made me think, is the earth core a superconductor?
- effie 7y ago
  Interesting idea. It would help to explain persistence of Earth's magnetic field.
- MichaelApproved 7y ago
  No. The core has pressure but it's way too hot to achieve super conductivity.
taneq 7y ago
Technically correct. The most annoying kind of correct.

bhaak 7y ago

> From a scientific standpoint, these results suggest that we might be entering a transition from discovering superconductors by empirical rules, intuition or luck to being guided by concrete theoretical predictions. That would be an exciting development.

PuffinBlue 7y ago

The interesting thing about this is that the work neatly fitted with existing theory: > Drozdov et al. observed this isotope effect and found that, compared with the lanthanum hydride samples, the critical temperature in lanthanum deuteride samples is lower by almost exactly the amount predicted by the theory. So like the article points out: > From a scientific standpoint, these results suggest that we might be entering a transition from discovering superconductors by empirical rules, intuition or luck to being guided by concrete theoretical predictions. Whilst this result might require huge pressures, steady progress towards a theory of super-conduction is an exciting thing indeed.

tigershark 7y ago
Also it may open the road to find metastable material at room temperature, although I don’t think that it’s the case for lantanium hydride.
djaque 7y ago
I wouldn't be too optimistic. The theory they are talking about is BCS theory. Most of the other high TC superconductors cannot be explained with it and high TC BCS superconductivity so far requires crazy environments with no clear path to making them easier to use. With the kinds of pressures required to make this happen, it's probably easier to just buy liquid nitrogen and use other materials.

stevespang 7y ago

At pressures of more than one million times Earth’s atmospheric pressure ? Totally academic, no real application in real world problems.

chiefalchemist 7y ago

> "Materials known as superconductors transmit electrical energy with 100% efficiency." What is the level of (in)efficieny for say power lines? And power cords, etc around the office/house? That is, of the electricity produced, how much is lost due to how it's transported? Does decentralizing production (e.g., solar panels on your own roof) help in any way?

krageon 7y ago
I'm normally not a fan of responding like this, but here goes: If you really do not know these things that is of course perfectly acceptable, but if they truly interested you you could very easily find the information about this out there. After all, it is knowledge you get in any highschool curriculum that even smells faintly of technical information. Given that you do not yet have this (as you miss other, related knowledge), giving you a good response that doesn't involve a lot of theory is very hard. Certainly a response that makes you aware of the nuances in this subject would involve some study. If that does not scare you, I invite you to take a look at a place like this: https://www.khanacademy.org/science/electrical-engineering/ee-electrostatics/ee-fields-potential-voltage/a/ee-electric-potential-voltage https://www.khanacademy.org/science/electrical-engineering/e... and study some of the source material.
- jacquesm 7y ago
  There is no such thing as a dumb question and if there is one thing that I love about HN it is that people will take the time to answer questions.
  - chiefalchemist 7y ago
    Not only will people answer, it's answers from people who actually know (and are willing to share).
- amirhirsch 7y ago
  This isn’t a good answer. On average in the US we lose 7% of power in transmission and 8% in power conversion. I pulled these numbers out of thin air, but it’s probably accurate to within a factor of 2 for wherever you are. A home solar power system might mean 7% lost in dc to ac and then you still lose 8% for conversion so basically 5-20% of all the power you produce is lost before it reaches its destination. A more didactic answer might start with defining power, P=IV (power equals current times voltage) and “ohm’s law” V=IR (voltage equals current times resistance) and suggest this means that the power lost to the resistance of transmission line with resistance R is P=I^2R. Since the current you send is proportion to the voltage (One megawatt can be 1Amp at 1000000 Volts or 1000Amp at 1000 Volts, you want to use as high voltage as possible when transmitting long distances. The limiting factor on voltage is the amount of insulation required. Usually power transmission uses three-phase alternating current, which sends power by varying the voltage on three lines each 120 degrees (1/3 period) offset from one another. It’s reasonable homework to read about why AC is better for transmission and also how three phase AC works and determine the economic value of laying three cables instead of two, with variables for the cost of wire, fixed costs per mile, and cost of electricity. ~50% of transmitted power is used to drive three-phase synchronous AC motors. Resistance is related to the resistivity (denoted with a Greek rho) of the material and the cross-sectional area (denoted A) and length (L) of the wire: R=rhoL/A Resistivity is a fundamental property of materials and is related to the free movement of the outer shell of electrons of atoms in a crystal lattice. Superconductors do not have resistance and can carry an extremely large current as a result. Unfortunately superconductors have a maximum magnetic field capacity and require extremely low temperatures requiring cooling with liquid helium or nitrogen.

oh_teh_meows 7y ago

I understand that the achievement in question was made in a high pressure environment; but if we get room temperature superconductors (at standard atm pressure), does that mean large scale hover cars/boards deployment will be viable as well [0]? [0] https://youtu.be/PXHczjOg06w https://youtu.be/PXHczjOg06w

wolfram74 7y ago
Room temperature super conductors are in the category of materials that will cause semi-magical transformations in society along side generation techniques that make .001$/KwH electricity, 1$/kwh electricity storage, or >200 gigaPa tensile strength materials for cheap.
adrianN 7y ago
It depends on how much it costs.

trebligdivad 7y ago

What's the highest pressure that can be achieved over a useful (1 meter?) distance? I find it amazing that they managed to scale up cryostats to 1km for superconducting powercables at low temperatures - it would just be interesting if they started scaling up high pressure environments.

acd 7y ago

Is the Sun a superconductor? The Sun consist of a high percentage of hydrogen ~73% and there must be really high pressure at the center. The suns central pressure is 2.5*10^11 bar according to nasa. https://en.m.wikipedia.org/wiki/Sun https://en.m.wikipedia.org/wiki/Sun https://nssdc.gsfc.nasa.gov/planetary/factsheet/sunfact.html https://nssdc.gsfc.nasa.gov/planetary/factsheet/sunfact.html

skykooler 7y ago
The sun is also at a temperature of millions of degrees. At these temperatures, there is no such thing as chemical bonds, and so the rules with hydrogen from the article don't apply.
- deleted 7y ago
  [deleted]
- agumonkey 7y ago
  interesting, is this a sub-field of physics ? high temperature physics or something ?
  - orbifold 7y ago
    Plasma physics I guess, plus magneto hydrodynamics, plus GR for really heavy stars.
    - agumonkey 7y ago
      dank u
  - pmalynin 7y ago
    High energy physics, yes.
    - agumonkey 7y ago
      danke schon

gwbas1c 7y ago

> lanthanum hydride compounds become superconducting at 250 K That's about -10F, or -23C. (And it would make a lot more sense to put that in the article. Most of us don't "think" in Kelvin.)

penagwin 7y ago
Oh thanks! Especially since the article says room temperature. I know a lot of people on HN are interested in superconductors but don't necessarily use K frequently if ever.
alkonaut 7y ago
That’s regular outdoor temperature in a lot of places. I wonder if there is any type of tech that is used in cold climates (or more on cold days) that would benefit from superconductors so they become more efficient when it’s most needed? Oh - it has to be at 1atm and -20 of course...
nine_k 7y ago
It's easy: "room temperature" is about 300K.

apo 7y ago

> Writing in Nature, Drozdov et al.1 report several key results that confirm that, when compressed to pressures of more than one million times Earth’s atmospheric pressure, lanthanum hydride compounds become superconducting at 250 K — a higher temperature than for any other known material. One million atmospheres is an important detail to leave out of the title.

yo1 7y ago

Has this been discussed here? Navy files for patent on room-temperature superconductor. https://phys.org/news/2019-02-navy-patent-room-temperature-superconductor.html https://phys.org/news/2019-02-navy-patent-room-temperature-s... "The application claims that a room-temperature superconductor can be built using a wire with an insulator core and an aluminum PZT (lead zirconate titanate) coating deposited by vacuum evaporation with a thickness of the London penetration depth and polarized after deposition. An electromagnetic coil is circumferentially positioned around the coating such that when the coil is activated with a pulsed current, a non-linear vibration is induced, enabling room temperature superconductivity. "This concept enables the transmission of electrical power without any losses and exhibits optimal thermal management (no heat dissipation)," according to the patent document, "which leads to the design and development of novel energy generation and harvesting devices with enormous benefits to civilization.""