TY - JOUR
T1 - Composition dependence of particle size distribution and giant magnetoresistance in Co-Al-O granular films
AU - Yakushiji, K.
AU - Mitani, S.
AU - Takanashi, K.
AU - Ha, J. G.
AU - Fujimori, H.
N1 - Funding Information:
We are grateful to Dr. M. Ohnuma and Dr. K. Hono, NRIM, for TEM observation, and Dr. S. Nagata, Dr. K. Takahiro and Prof. S. Yamaguchi, IMR, Tohoku University, for the RBS analyses. Our thanks are also due to Dr. S. Ohnuma, RIEMM, for their sample preparation. This work was partly supported by a Grant-In-Aid for Scientific Research on Priority Area from the Ministry of Education, Science, Sports and Culture (No. 09236101) and by a JSPS Research Project for the Future Program (JSPS-RFTF 96P00106). One of the authors (K. Yakushiji) is grateful to the Research Fellowship of the JSPS for Young Scientists.
PY - 2000
Y1 - 2000
N2 - We have investigated the particle size distributions in Co-Al-O insulating granular films with various Co concentrations (xCo) by analyzing the superparamagnetic behavior of magnetization. The comparison between the particle size distributions estimated from the magnetization analysis and the TEM observation has made it possible to distinguish between the topological size and the magnetic size of particles. It is suggested that some Co particles couple ferromagnetically to form larger magnetic clusters as xCo increases. The magnetoresistance (MR) ratio decreases slightly with xCo for xCo > 36 at %, which is different from the result for metallic granular systems where the MR ratio decreases drastically with the coarsening of magnetic clusters.
AB - We have investigated the particle size distributions in Co-Al-O insulating granular films with various Co concentrations (xCo) by analyzing the superparamagnetic behavior of magnetization. The comparison between the particle size distributions estimated from the magnetization analysis and the TEM observation has made it possible to distinguish between the topological size and the magnetic size of particles. It is suggested that some Co particles couple ferromagnetically to form larger magnetic clusters as xCo increases. The magnetoresistance (MR) ratio decreases slightly with xCo for xCo > 36 at %, which is different from the result for metallic granular systems where the MR ratio decreases drastically with the coarsening of magnetic clusters.
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U2 - 10.1016/S0304-8853(99)00813-6
DO - 10.1016/S0304-8853(99)00813-6
M3 - Article
AN - SCOPUS:0033885983
VL - 212
SP - 75
EP - 81
JO - Journal of Magnetism and Magnetic Materials
JF - Journal of Magnetism and Magnetic Materials
SN - 0304-8853
IS - 1
ER -