Magnetic dead layer in ferromagnetic manganite nanoparticles

J. CURIALE; M. GRANADA; H. E. TROIANI; R. D. SANCHEZ; A. G. LEYVA; P. LEVY; K. SAMWER

APPLIED PHYSICS LETTERS

AMER INST PHYSICS

Año: 2009 vol. 95 p. 431061 - 431063

0003-6951

We present experimental evidence on the physical origin of a magnetic dead layer (MDL) inmanganite nanoparticles. The studied nanoparticles constitute the wall of La0.67Sr0.33MnO3 andLa0.67Ca0.33MnO3 manganite nanotubes. Magnetic properties analysis and high resolutiontransmission electron microscopy show a shell of approximately 2 nm thickness with differentproperties from the core. In this shell the atoms are in a noncrystalline array that perfectly explainsthe 50% reduction of the magnetization compared to the bulk. Moreover, we present experimentalevidence that the internal magnetic structure of the MDL is constituted by small ferromagneticclusters in a frustrated configuration.