•  1
    The effect of Fe doping on the Mn site in the ferromagnetic and the antiferromagnetic phases of La1-xCaxMnO3 has been studied. The same ionic radii of Fe3+ and Mn3+ cause no structure change in either series, yet conduction and ferromagnetism have been consistently suppressed by Fe doping. Colossal magnetoresistance has been shifted to lower temperatures, and in some cases enhanced by Fe doping. Doping with Fe bypasses the usually dominant lattice effects, but depopulates the hopping electrons a…Read more
  • Charge ordering and magnetoresistance in Nd 1-x Ca x MnO 3 due to reduced double exchange
    with X. W. Wu, K. H. Ahn, T. Sulchek, C. L. Chien, and J. Q. Xiao
    Structural, transport, and magnetic properties of Nd1-xCaxMnO3 have been studied to probe the consequence of strong lattice distortion and reduced double exchange. Charge ordering has been observed over a large composition range of 0.30≤x≤0.80. For 0.33≤x≤0.40, at low temperatures, a magnetic field induces a first-order antiferromagnetic semiconductor to ferromagnetic metal transition and reduces the resistance by several orders of magnitude. These results illustrate the competition between doub…Read more