“ Magnetic interactions in ferromagnetic manganite nanotubes of different diameters”

J. CURIALE, R. D. SÁNCHEZ, H. E. TROIANI, A. G. LEYVA AND P. LEVY.

APPLIED SURFACE SCIENCE

ELSEVIER SCIENCE BV

Año: 2007 p. 368 - 370

0169-4332

In this work we present a magnetic study of La0.67Sr0.33MnO3 (LSMO) and La0.67Ca0.33MnO3 (LCMO) nanotubes with nominal external diameters (φ{symbol}) of 100, 200, 600 and 800 nm. The 800 nm diameter nanotubes have walls of around 50 nm thickness in all the cases. The walls are constituted by an assembly of nanoparticles with a non-Gaussian size distribution presenting a maximum at 24 ± 6 nm (LSMO) and 25 ± 8 nm (LCMO). We carried out isothermal remanent magnetization (IRM) and dc demagnetization (DCD) experiments. We determined that the crystallites are single magnetic domains with a magnetic dead layer on the surface which avoids exchange interactions among grains. We conclude that the dominating interactions are of dipolar type of the same magnitude for all the samples. © 2007 Elsevier B.V. All rights reserved.