SPIN-LATTICE RELAXATION PROCESSES IN TYPE 2 SUPERCONDUCTORS

The spin-lattice relaxation times of vanadium-titanium and niobium-zirconium alloys have been measured as a function of temperature at severa magnetic fields in the superconducting phase. It has been found that above 1/4 Tc the temperature dependence is according to the BCS theory while for lower temperatures the relaxation rates are faster and are proportional to the magnetic field. Extrapolating 1/T1 to H=0 gives the expected BCS values. This behavior is accounted for by the presence of fiuxoids in the metals. Also, from the experimental results the coherence lengths can be estimated. © 1968, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.