Abstract
Ferromagnetism (T c ) and negative magnetoresistive properties (maximum at 30 K) are observed in the monolayered manganites Ca 2–x Ln x MnO 4 (Ln=Pr, Sm, Gd, Ho and 0<x7≤0.20) despite their pure bidimensional character. A detailed structural study was carried out using X-ray diffraction, electron diffraction, and high resolution electron microscopy. This shows that they exhibit an orthorhombic cell, with a≊b≊ap2, c≊√12 A and Aba2 or Abma as possible space groups. In all these oxides, (001)-type twinning is observed, on a unit cell scale, creating in this way a local periodicity of 24 A. In the x=0.08 doped samples, it is observed that the microstructural state is strongly dependant on the synthesis process but it does not affect the magnetotransport properties.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
