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Enter e-mail address This e-mail address will be used to create your account. Reset your password. Please enter the e-mail address you used to register to reset your password Enter e-mail address. Registration complete. Superconductivity Research update Refrigerator cools one electron at a time 24 Jan Hamish Johnston. Want to read more? Register to unlock all the content on the site. For each case, we assume that the hot and cold reservoirs, and the working substance are in thermal equilibrium such that their temperatures are identical before the refrigerator is turned on.
Learn about our response to COVID , including freely available research and expanded remote access support. Manikandan, Francesco Giazotto, and Andrew N. Jordan Phys. Applied 11 , — Published 13 May Abstract We propose a solid-state refrigeration technique based on repeated adiabatic magnetization and demagnetization cycles of a superconductor, which acts as the working substance.
Research Areas. Cooper pairs Mesoscopics. Physical Systems. Issue Vol. Authorization Required. Log In. Figure 1 a Steps of the refrigeration cycle. Figure 2 a Energy diagram of the junctions when the working substance is in the hot superconducting state.
Figure 3 a Repeated cooling cycles of a junction refrigerator [see Fig. Figure 4 a We assume that the phonon-mediated heat transport Kapitza coupling between the working substance and the hot reservoir can be suppressed by choosing the tunnel barrier appropriately, while the substrate is isolated by suspending it as a membrane to reduce Kapitza coupling.
The bottom layer of the stack is a sheet of the superconductor niobium, which acts as a hot reservoir, akin to the environment outside a traditional refrigerator. The middle layer is the superconductor tantalum, which is the working substance, akin to the refrigerant in a traditional refrigerator. The top layer is copper, which is the cold reservoir, akin to the inside of a traditional fridge.
When the physicists slowly apply a current of electricity to the niobium, they generate a magnetic field that penetrates the middle tantalum layer, causing its superconducting electrons to unpair, transition to their normal state, and cool down.
The scientists then slowly turn off the magnetic field, causing the electrons in the tantalum to pair and transition back into a superconducting state, and the tantalum becomes hotter than the niobium layer.
Excess heat is then transferred to the niobium. The cycle repeats, maintaining a low temperature in the top copper layer. Sreenath K.
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