5 In summary, above 150K the electronic specific heats for the three samples are large and almost identical. For the x = 0 sample there is a large and almost first order anomaly at the SDW transition at T$_{0}$ = 136K, whilst the corresponding anomaly for the x = 0.1 sample at T$_{0}$ = 135K is smaller and broader and more closely resembles a second order phase transition. At low temperatures, γ for these two samples is strongly reduced by the SDW gap by factors of 11 and 5 for x = 0 and 0.1 respectively. In the x = 0.3 sample the large superconducting anomaly and associated value of S/T ( T$_{c}$ ) shows that the under- lying normal state γ at low temperature is close to its high temperature value. This suggests that as x reduces, the growth of the SDW gap and consequent reduction in the density of states is responsible for the disappearance of superconductivity. The temperature dependence of γ ( x = 0.3) supports a nodeless superconducting gap func- tion that is strongly anisotropic about the Fermi surface, possibly due to the presence of multiple gaps. We gratefully acknowledge funding from the Engineer- ing and Physical Sciences Research Council (U.K.) and the Swiss National Science Foundation pool MaNEP. [1] J. Loram, K. A. Mirza, J. R. Cooper, W. Y. Liang, and J. M. Wade, J. Supercon. 7 , 243 (1994). [2] J. W. Loram, K. A. Mirza, J. R. Cooper, and J. L. Tallon, J. Phys. Chem. Solids 59 , 2091 (1998). [3] J. W. Loram, J. L. Luo, J. R. Cooper, W. Y. Liang, and J. L. Tallon, Physica C 341–348 , 831 (2000). [4] J. W. Loram, J. Luo, J. R. Cooper, W. Y. Liang, and J. L. Tallon, J. Phys. Chem. Solids. 62 , 59 (2001). Ginsburg-Landau parameter κ = H$_{c}$$_{2}$/H$_{c}$ √ 2, lower crit- ical field H$_{c}$$_{1}$ = ( φ$_{0}$ ln κ ) / (4 πλ $^{2}$), and superconducting coherence length ξ = ( φ$_{0}$/ 2 πH$_{c}$$_{2}$ ) 1 / $^{2}$. The temperature dependencies of these quantities is plotted in Fig. 5. The values shown are polycrystalline averages. The large κ ≈ 130 indicates the strong type II nature of this material. Our H$_{c}$$_{2}$ values are very similar to those obtained from radio frequency penetration depth measurements on a single crystal with x = 0.45[19], and the value we ob- tain for λ (0) ≈ 260nm is similar to those measured by infrared spectroscopy[20] and tunnel diode resonator[21] techniques. [5] J. W. Loram, J. L. Tallon, and W. Y. Liang, Phys. Rev. B 69 , 060502(R) (2004). [6] J. L. Tallon, J. G. Storey, and J. L. Loram, arXiv:0908.4428 (2009). [7] J. W. Loram, J. Phys. E 16 , 367 (1983). [8] H. Chen, Y. Ren, Y. Qiu, W. Bao, R. H. Liu, G. Wu, T. Wu, Y. L. Xie, X. F. Wang, Q. Huang, et al., EPL 85 , 17006 (2009). [9] J. K. Dong, L. Ding, H. Wang, X. F. Wang, T. Wu, G. Wu, X. H. Chen, and S. Y. Li, New J. Phys. 10 , 123031 (2008). [10] M. Rotter, M. Tegel, I. Schellenberg, F. M. Schappacher, R. P¨ ottgen, J. Deisenhofer, A. G¨ unther, F. Schrettle, A. Loidl, and D. Johrendt, New J. Phys. 11 , 025014 (2009). [11] K. Selte, A. Kjekshus, and A. F. Andresen, Acta Chem. Scand. 26 , 3101 (1972). [12] N. W. Aschcroft and N. D. Mermin, Solid State Physics. (Holt Saunders, 1976). [13] S. A. J. Kimber, A. Kreyssig, Y.-Z. Zhang, H. O. Jeschke, R. Valenti, F. Yokaichiya, E. Colombier, J. Yan, T. C. Hansen, T. Chatterji, et al., Nature Mat. 8 , 471 (2009). [14] S. L. Bud’ko, N. Ni, S. Nandi, G. M. Schmiedeshoff, and P. C. Canfield, Phys. Rev. B 79 , 054525 (2009). [15] J. W. Loram, K. A. Mirza, J. R. Cooper, and W. Y. Liang, Phys. Rev. Lett. 71 , 1740 (1993). [16] L. X. Yang, Y. Zhang, H. W. Ou, J. F. Zhao, D. W. Shen, B. Zhou, J. Wei, F. Chen, M. Xu, C. He, et al., Phys. Rev. Lett. 102 , 107002 (2009). [17] G. Mu, H. Luo, Z. Wang, L. Shan, C. Ren, and H. H. Wen, Phys. Rev. B 79 , 174501 (2009). [18] Z. Hao and J. R. Clem, Phys. Rev. Lett. 67 , 2371 (1991). [19] M. M. Altarawneh, K. Collar, C. H. Mielke, N. Ni, S. L. Bud’ko, and P. C. Canfield, Phys. Rev. B 78 , 220505(R) (2008). [20] G. Li, W. Z. Hu, J. Dong, Z. Li, P. Zheng, G. F. Chen, J. L. Luo, and N. L. Wang, Phys. Rev. Lett. 101 , 107004 (2008). [21] R. Prozorov, M. A. Tanatar, R. T. Gordon, C. Martin, H. Kim, V. G. Kogan, N. Ni, M. E. Tillman, S. L. Bud’ko, and P. C. Canfield, Physica C 469 , 582 (2009).