skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Super-heavy electron material as metallic refrigerant for adiabatic demagnetization cooling

Abstract

Low-temperature refrigeration is of crucial importance in fundamental research of condensed matter physics, because the investigations of fascinating quantum phenomena, such as superconductivity, superfluidity, and quantum criticality, often require refrigeration down to very low temperatures. Currently, cryogenic refrigerators with 3He gas are widely used for cooling below 1 Kelvin. However, usage of the gas has been increasingly difficult because of the current world-wide shortage. Therefore, it is important to consider alternative methods of refrigeration. We show that a new type of refrigerant, the super-heavy electron metal YbCo 2Zn 20, can be used for adiabatic demagnetization refrigeration, which does not require 3He gas. This method has a number of advantages, including much better metallic thermal conductivity compared to the conventional insulating refrigerants. We also demonstrate that the cooling performance is optimized in Yb 1$-$xSc xCo 2Zn 20 by partial Sc substitution, with x ~ 0.19. The substitution induces chemical pressure that drives the materials to a zero-field quantum critical point. This leads to an additional enhancement of the magnetocaloric effect in low fields and low temperatures, enabling final temperatures well below 100 mK. This performance has, up to now, been restricted to insulators. For nearly a century, the same principle ofmore » using local magnetic moments has been applied for adiabatic demagnetization cooling. Lastly, this study opens new possibilities of using itinerant magnetic moments for cryogen-free refrigeration.« less

Authors:
 [1];  [2];  [2];  [3];  [3];  [4]
  1. Gottingen Univ. (Germany). I. Physikalisches Inst.; Kyoto Univ. (Japan). Dept. of Physics; Univ. of Augsburg (Germany). Experimental Physics VI, Center for Electronic Correlations and Magnetism
  2. Gottingen Univ. (Germany). I. Physikalisches Inst.
  3. Ames Lab. and Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy
  4. Gottingen Univ. (Germany). I. Physikalisches Inst.; Univ. of Augsburg (Germany). Experimental Physics VI, Center for Electronic Correlations and Magnetism
Publication Date:
Research Org.:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1342908
Report Number(s):
IS-J-9139
Journal ID: ISSN 2375-2548
Grant/Contract Number:
AC02-07CH11358
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Science Advances
Additional Journal Information:
Journal Volume: 2; Journal Issue: 9; Journal ID: ISSN 2375-2548
Publisher:
AAAS
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Adiabatic demagnetization refrigeration; heavy fermion; quantum critical point

Citation Formats

Tokiwa, Yoshifumi, Piening, Boy, Jeevan, Hirale S., Bud'ko, Sergey L., Canfield, Paul C., and Gegenwart, Philipp. Super-heavy electron material as metallic refrigerant for adiabatic demagnetization cooling. United States: N. p., 2016. Web. doi:10.1126/sciadv.1600835.
Tokiwa, Yoshifumi, Piening, Boy, Jeevan, Hirale S., Bud'ko, Sergey L., Canfield, Paul C., & Gegenwart, Philipp. Super-heavy electron material as metallic refrigerant for adiabatic demagnetization cooling. United States. doi:10.1126/sciadv.1600835.
Tokiwa, Yoshifumi, Piening, Boy, Jeevan, Hirale S., Bud'ko, Sergey L., Canfield, Paul C., and Gegenwart, Philipp. 2016. "Super-heavy electron material as metallic refrigerant for adiabatic demagnetization cooling". United States. doi:10.1126/sciadv.1600835. https://www.osti.gov/servlets/purl/1342908.
@article{osti_1342908,
title = {Super-heavy electron material as metallic refrigerant for adiabatic demagnetization cooling},
author = {Tokiwa, Yoshifumi and Piening, Boy and Jeevan, Hirale S. and Bud'ko, Sergey L. and Canfield, Paul C. and Gegenwart, Philipp},
abstractNote = {Low-temperature refrigeration is of crucial importance in fundamental research of condensed matter physics, because the investigations of fascinating quantum phenomena, such as superconductivity, superfluidity, and quantum criticality, often require refrigeration down to very low temperatures. Currently, cryogenic refrigerators with 3He gas are widely used for cooling below 1 Kelvin. However, usage of the gas has been increasingly difficult because of the current world-wide shortage. Therefore, it is important to consider alternative methods of refrigeration. We show that a new type of refrigerant, the super-heavy electron metal YbCo2Zn20, can be used for adiabatic demagnetization refrigeration, which does not require 3He gas. This method has a number of advantages, including much better metallic thermal conductivity compared to the conventional insulating refrigerants. We also demonstrate that the cooling performance is optimized in Yb1$-$xScxCo2Zn20 by partial Sc substitution, with x ~ 0.19. The substitution induces chemical pressure that drives the materials to a zero-field quantum critical point. This leads to an additional enhancement of the magnetocaloric effect in low fields and low temperatures, enabling final temperatures well below 100 mK. This performance has, up to now, been restricted to insulators. For nearly a century, the same principle of using local magnetic moments has been applied for adiabatic demagnetization cooling. Lastly, this study opens new possibilities of using itinerant magnetic moments for cryogen-free refrigeration.},
doi = {10.1126/sciadv.1600835},
journal = {Science Advances},
number = 9,
volume = 2,
place = {United States},
year = 2016,
month = 9
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Save / Share:
  • The theoreticaL basis is laid for cooling by isentropic reduction of magnetic fields in paramagnetic salts. The requirements for successful nuclear cooling are discussed. A new nuclear cooling apparatus was used to show that during the warming-up step the conduction electrons are in thermal contact with the electronic stage. The temperature dependence of the relaxation time and interaction energy was determined. The effects of heat contact during demagnetization on the final temperature was studied. Work in this field is reviewed. (D.L.C.)
  • In an effort to better understand the various factors involved in refrigeration by adiabatic demagnetization, we have set up a computer model of a paramagnetic salt in contact with liquid $sup 3$He. This model has been used to study the cooling of the $sup 3$He from an initial temperature of 20 mK, which is typical of the temperature achieved in a dilution refrigerator. The effects of various demagnetization schedules, heat leaks, and varying ratios of salt to liquid have been studied. The model was used to simulate an actual demagnetization and gave excellent agreement with measured temperatures. It is alsomore » shown how the model can be extended to the case of nuclear demagnetization. 4 figures. (auth)« less
  • The construction and performance of a single stage nuclear demagnetization apparatus utilizing 0.267 mole of praseodymium nickel material is described. An optimization procedure to minimize entropy production during the demagnetization of the hyperfine enhanced material has been developed which enabled the cryostat to cool a liquid-/sup 3/He sample to a temperature of 350 ..mu..K. The effects of measured heat leaks and inferred eddy-current heating are accounted for satisfactorily in a model of this procedure.