添加Ho之La0.67Ca0.33MnO3材料的電性、磁性及磁阻研究
Date Issued
2005
Date
2005
Author(s)
洪舜賢
DOI
zh-TW
Abstract
In this experiment we add Ho(0.2~2.0 mol%) to La0.67Ca0.33MnO3 (LCMO) sample, and sputtering thin films . The bulks whose metal-insulator (M-I) transition temperature T MI of Ho-doped bulk samples are enhanced about 15K compared with Ho-free LCMO. Hox-La0.67Ca0.33MnO3 films with x = 0, 0.2, 0.4 and 0.6 % mole of Ho have been prepared by dc magnetron sputter -ing. The thin films were grown on SrTiO3(100) substrates with the substrate temperature at 600℃ and the thickness of the films was about 30nm. It has been found from X-ray diffraction that only superlattice peaks corresponding to (002) and (004) planes are present and the peak positions shift to larger angles as the amount of Ho is increased. Furthermore, the magnetic transition temperature Tc and metal- insulator (M-I) transition temperature TMI are enhanced about 25~50K compared with Ho-free LCMO thin film. The enhancement maximum in x ≒ 0.4 occurs at its ordering temperature around 280K.
Subjects
龐磁阻
CMR
Type
thesis
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