Thermal magnetoresistance of gallium and its use as a heat switch

✍ Scribed by F.W. Gorter; A.R. Miedema

• Publisher: Elsevier Science
• Year: 1968
• Tongue: English
• Weight: 150 KB
• Volume: 8
• Category: Article
• ISSN: 0011-2275
• DOI: 10.1016/0011-2275(68)90047-7

✦ Synopsis

THE SUPERCONDUCTIVE heat switch has been in use at temperatures below 1 °K for a long time. Near 1 °K these heat switches become rather ineffective and a maximum ratio Wn/Wo of about 60 at 1 °K is reached with lead (see the discussion by Peshkovl). For various applications a higher ratio near 1 °K is very important, which may be realized by using the increase of thermal resistance in a magnetic field, as has been suggested by Mendelssohn and Rosenberg. 2 Recently Laudy and Knol 3 showed the suggestion to be useful in practice; using pure cadmium they reached a value for Wn/14/o of 700 in 26 kG at 2°K including the contact resistance.

As shown by Reed and Marcus a the electrical magnetoresistance for gallium single crystals is very high. The magnetoresistance is greatest for the current along the b-axis and the field parallel to the crystallographic c-axis, the ratio Rn/Ro being 45 x 104 for H = 15 kG. This makes gallium attractive for use as a magnetoresistance thermal switch.