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Estimation of Magnetic Energy Distribution in Co84Cr16Ta4 Magnetic Thin Films from EFTEM

Published online by Cambridge University Press:  01 February 2011

Jafar F. Al-Sharab
Affiliation:
[email protected], Rutgers University, Materials Science and Engineering, 607 Taylor RD, Piscataway, NJ, 08854, United States, 732 445 5615
James E Wittig
Affiliation:
[email protected], Vanderbilt University, Electrical Engineering and Computer Science, Nashville, TN, 37234, United States
James Bentley
Affiliation:
[email protected], Oak Ridge National Laboratory, Materials Science and Technology Division, Oak Ridge, TN, 37831, United States
Neal Evans
Affiliation:
[email protected], Oak Ridge National Laboratory, Materials Science and Technology Division, Oak Ridge, TN, 37831, United States
Gerardo Bertero
Affiliation:
[email protected], Komag Inc., San Jose, CA, 95131, United States
Tom Yamashita
Affiliation:
[email protected], Komag Inc., San Jose, CA, 95131, United States
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Abstract

Magnetic thin films of Co80Cr16Ta4 were sputtered onto identical CrMo seed-layers at −200 V bias and 3 different substrate temperatures (150, 200, and 250°C). Energy-filtered transmission electron microscopy (EFTEM) was performed to analyze Cr levels at the grain boundaries as well as inside the grains. These quantitative Cr measurements were used to estimate the local values of magnetocrystalline anisotropy (Ku) and, together with grain size distributions, calculate the product of Ku and the grain volume (KuV), a quantity which is a measure of thermal stability. The results show that the coercivity as well as the percentage of stable grains increased with increasing substrate temperature. The increase in the number of stable grains is produced by the enhancement in the Ku value from Cr depletion of the grain interiors and the magnetic decoupling between the grains from Cr grain boundary segregation.

Type
Research Article
Copyright
Copyright © Materials Research Society 2008

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