Enhancement of Ferromagnetism in the Colossal-Magnetoresistance Layered Manganite La^sub 1.2^Ba^sub 1.8^Mn^sub 2-x^Ru^sub x^O^sub 7^ (x = 0, 0.1, 0.5, and 1)

Journal of Electronic Materials, Nov 2004 by Sudhakar, Nori, Rajeev, K P, Nigam, A K

CONCLUSIONS

We find that Ru doping affects the MR and the electrical transport properties significantly. High values of MR are obtained, and there is considerable MR present even at 225 K in case of the x = 0.5 sample. The MR has been found to increase marginally with Ru doping from 54% for the undoped sample to 58% for the x = 0.5 and decreases to 46% for the x = 1 sample at 10 K. Very little hysteresis is found in the MR. From fitting the p-H isothermal curves, we find that the curvature changes from concave up to linear-like as the temperature is raised from 5 K to 225 K for the x = 0.5 Ru-doped sample. The low-temperature MR is found to vary as a square root of the applied magnetic field.

ACKNOWLEDGEMENTS

One of the authors (NS) gratefully acknowledges the excellent hospitality and the partial financial support extended by Professor Jagdish Narayan and Dr. Ashutosh Tiwari, NCSU, Raleigh, NC, USA, during his visit. The partial financial support from Stirling Cryogenics India Limited is also gratefully appreciated. The authors thank R.S. Ningthoujam, UT (Kanpur, India), for his help.

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