R. Mahendiran

Effect of particle size on the giant magnetoresistance of La0.7Ca0.3MnO3

Effect of particle size on the electron transport and magnetic properties of La0.7Ca0.3MnO3 has been investigated. While the ferromagnetic Tc, low field magnetic susceptibility, and insulator‐metal transition are markedly affected by the particle size, the maximum magnetoresistance exhibited by the samples near Tc is not sensitive to the particle size. However, the magnetoresistance at 4.2 K increases with decrease in particle size, suggesting a substantial contribution by the grain boundaries. Preliminary measurements on La0.7Sr0.3MnO3 samples of different particle sizes also corroborate the above conclusions.

Ultrasharp magnetization steps in perovskite manganites.

We report a detailed study of steplike metamagnetic transitions in polycrystalline Pr0.5Ca0.5Mn0.95Co0.05O3. The steps have a sudden onset below a critical temperature, are extremely sharp (width <2x10(-4) T), and occur at critical fields which are linearly dependent on the absolute value of the cooling field in which the sample is prepared. Similar transitions are also observed at low temperature in non-Co doped manganites, including single crystal samples. These data show that the steps are an intrinsic property, qualitatively different from either previously observed higher temperature metamagnetic transitions in the manganites or metamagnetic transitions observed in other materials.

Saturated ferromagnetism and magnetization deficit in optimally annealed Ga1-xMnxAs epilayers

La_{0.7}Sr_{0.3}Mn0_3

Giant magnetoresistance, charge ordering and other novel properties of perovskite manganates

samples prepared by heating the precursor gel at different temperatures in the 873 - 1473 K range show nearly the same ferromagnetic transition temperature

Room temperature giant magnetoresistance in La1-xPbxMnO3

(T_c\approx 392\pm 4K)

Composition dependence of magnetocaloric effect in Sm1−xSrxMnO3(x=0.3–0.5)

, but the insulator- metal like transition temperatures

Composition dependence of giant magnetoresistance in La1−xCaxMnO3 (0.1 ≤ x ≤ 0.9)

(T_p)

Instability of metal-insulator transition against thermal cycling in phase separated Cr-doped manganites

are significantly lower

Electrical, magnetic, magnetodielectric, and magnetoabsorption studies in multiferroic GaFeO3

(\approx 170 K)