Magnetic and orbital textures in CMR manganites studied with NMR

G. Papavassiliou1, M. Pissas1, G. Diamantopoulos1, M. Belesi2, C. Dimitropoulos3, and J. P. Ansermet3
1 Institute of Materials Science, NCSR Demokritos, 153 10 Aghia Paraskevi, Attiki, Greece.
2 Dept. of Physics, Ames Laboratory, Iowa State University, Ames, Iowa 50011.
3 Institut de Physique Experimentale, EPFL-PH-Ecublens, 1015-Lausanne, Switzerland.

The study of strong electron correlations in transition metal oxides with modern microscopy and diffraction techniques unveiled a fascinating world of nanosize textures in the spin, charge, and crystal structure. Examples range from high Tc superconducting cuprates and nickelates, to hole doped manganites and cobaltites. However, in many cases the appearance of these textures is accompanied with "glassiness" and multiscale/ multiphase effects, which complicate significantly their experimental verification. Here, we demonstrate how nuclear magnetic resonance may be uniquely used as a probe of nano/micro-size magnetic and orbital textures in ferromagnetic colossal magnetoresistive manganites of the La1-xCaxMnO3 and La1-xSrxMnO3 families. Especially, the low temperature ferromagnetic and insulating phase in the low doping regime, reveals nanoscale phase separation and strong wipe-out of the NMR signals, in analogy with the wipe-out effect observed in superconducting cuprates and nickelates.

References
[1] G. Papavassiliou, M. Belesi, M. Fardis, C. Dimitropoulos, Phys. Rev. Lett. 87, 177204 (2001).
[2] M. Belesi, G. Papavassiliou, M. Fardis, M. Pissas, J. Wegrowe, and C. Dimitropoulos, Phys. Rev. B. 63, 180406R (2001).
[3] G. Papavassiliou, M. Pissas, M. Belesi, M. Fardis, J. Dolinsek, C. Dimitropoulos, and J. P. Ansermet, Phys. Rev. Lett. 91, 147205 (2003).
[4] G. Papavassiliou, M. Pissas, M. Belesi, M. Fardis, D. Carlier, C. Dimitropoulos, J. P. Ansermet, and J. Dolinsek, Europhys. Lett. 68, 453 (2004).
[5] G. Papavassiliou, M. Pissas, M. Belesi, M. Fardis, D. Stamopoulos, A. Kontos, M. Hennion, J. Dolinsek, J. P. Ansermet, C. Dimitropoulos cond-mat/0412371.