Hall effect measurements on type II superconductors

Hall Effect in Dirty Type-II Superconductors

“…The limiting Hall angle is independent of the temperature and proportional to (TAOO)"" 1 , where r is the relaxation time of electrons, and A 00 is the BCS energy gap at T =0°K and in the absence of magnetic field" The above results [i.e., Eqs c (9) and (11)] are consistent with experiments on Nb-Ta alloys by Niessen et al 1 ' 2 and those on V-based alloys by Usui et al, 3 although we need accurate informa-tion about rA 00 for those alloys in order to carry out a quantitative comparison c Very recently Weijsenfeld 4 proposed a phenomenological model, in which he made an ad hoc assumption that the relaxation time of the normal electrons inside the vortex core is A^"* 1 rather than T, and arrived at qualitatively much the same conclusion as the present theory 0 However it is quite difficult to justify his choice of the relaxation time from a microscopic point of vieWo Furthermore we believe that his estimate of rA 00 for various alloys is generally too small and that the good agreement he found is partly fortuitous" We note here that the present calculation can be easily extended to cover the Hall effect in the intermediate state of a type-1 superconductor (provided the temperature is not too low where H 0 is the external field and n is the diamagnetization coefficient,, In the dilute limit of the vortex lines [i.e", B «H C (T)] 9 Eq. (8) reduces to *(0) = fl llm*(2»=^ (13) which is identical to Eq c (11) 0 Finally we would like to conclude this note with a remark on the Hall effect in a pure type-II superconductor.…”

Thermomagnetic Effects in Superconductors

“…When a superconductor is in the mixed or intermediate state, the situation must be quite different because both electrical resistance 6 and the Hall effect 18 can be observed. These observations are not in contradiction with the above argument because the effects are observed only when the superfluid velocity and vector potential vary with time as is the case in the flux flow state.…”

Der direkte Nachweis von Flußlinienbewegungen in stromdurchflossenen Supraleitern

“…Sowohl im Zwischenzustand von Typ I-Supraleitern als auch im Mischzustand von Typ 11-Supraleitern wird bei hinreichend hohen Transportstromen, die senkrecht zum angelegten Magnetfeld flieBen, ein elektrischer Widerstand [l bis 51 und ein Halleffekt [6] …”

“…Sowohl im Zwischenzustand von Typ I-Supraleitern als auch im Mischzustand von Typ 11-Supraleitern wird bei hinreichend hohen Transportstromen, die senkrecht zum angelegten Magnetfeld flieBen, ein elektrischer Widerstand [l bis 51 und ein Halleffekt [6] beobachtet. Die verschiedenen Modelle [7 bis 111 zur Erklarung der damit verbundenen Energiedissipation gehen von der Hypothese aus, dalj der elektrisohe Widerstandder keinesfalls ein Ohmscher Widerstand im ublichen Sinne istmit der Bewegung von FluBlinien, bzw.…”