Thin films of Al-substituted cobalt ferrite layers on thermally oxidized silicon wafers were fabricated via the sol-gel method with various annealing temperatures. Structural and magnetic properties of the films were investigated with thermogravimetric and differential thermal analysis (TG-DTA), an x-ray diffractometer, vibrating sample magnetometer (VSM), and atomic force microscopy (AFM). TG-DTA measurements showed exothermic reaction peak at 285° C. CoAl0.2Fe1.8O4 thin films that fired at and above 400°C had a single cubic spinel structure without any preferred crystallite orientation. Lattice constants monotonically decreased from 0.8381 to 0.8354 nm with increasing annealing temperature from 400 to 800°C. As annealing temperature increased from 400 up to 800°C, grain size increased from 4.6 to 25.4 nm, whereas the surface roughness was minimized at 700°C with a value of 2.0 nm. Parallel and perpendicular coereivity at room temperature showed maximum values of 1980 and 2490 Oe, respectively, in the sample annealed at 700° C. Coercivity was shown to be strongly dependent not only on annealing temperature but also on surface roughness.
|Number of pages||3|
|Journal||IEEE Transactions on Magnetics|
|Issue number||5 I|
|Publication status||Published - 2002 Sep|
|Event||2002 International Magnetics Conference (Intermag 2002) - Amsterdam, Netherlands|
Duration: 2002 Apr 28 → 2002 May 2
Bibliographical noteFunding Information:
Manuscript received February 5, 2002. This work was supported by the Korea Science and Engineering Foundation (R01-1997-00109) and the Research Center for Advanced Magnetic Materials (KOSEF) at Chungnam National Laboratory. S. J. Kim and C. S. Kim are with the Department of Physics, Kookmin University, Seoul, Korea (e-mail: email@example.com). K.-H. Jeong is with the Department of Physics, Yonsei University, Seoul, Korea. Digital Object Identifier 10.1109/TMAG.2002.801965.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering