A simple and sensitive apparatus for Seebeck coefficient measurement down to 77 K

A simple and sensitive experimental set-up for low temperature Seebeck coefficient measurement has been fabricated using copper block sandwich type technique (dc) down to 77 K. The flexibility of the system has been demonstrated by carrying out measurements on different type of samples (Platinum, YBCO, and Metallic glass) with different geometry (wire, pellet and foil). In order to attain better stability and sensitivity, some new techniques are proposed by applying the concept isothermal zone. The effective sample holder design helps for much easier way of sample mounting and the present techniques employed for thermocouple mounting and signal leads contact increase electrical and thermal stabilities of the system with better sensitivity and lesser thermal time constant. The system is sensitive to a change of 25 mK in gradient (YBCO with S=5 micro Volt/Kelvin). We could attain a stability of /spl plusmn/15 nV, /spl plusmn/3 mK and /spl plusmn/1 mK in signal, gradient and temperature respectively.