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【期刊论文】Studies on magnetic aftereffect of Fe3O4 nano-particles
侯登录, Deng-lu Hou, Zi-xia Du, Cai-xia Yue, Qing-hua Liu
Journal of Alloys and Compounds 429 (2007) 40-45,-0001,():
-1年11月30日
The magnetic aftereffects of Fe3O4 nano-particles were simulated by Preisach hysteresis model, the results showed excellent agreement with the experiment data. The simulating results showed that due to the wide distribution of interaction field, magnetization decay followed typical logarithmic time dependence, and the decay occurred more rapidly for field closer to the coercivity. The thermal fluctuation field and activation volume were also obtained, which are the main characteristics of the thermal fluctuations in magnetic recording medium. From the fact that activation volume is larger than the mean particle size, we deduced the reversal magnetization mechanism. One set of parameters used in simulating hysteresis loops and magnetic aftereffects has unified the hysteresis and magnetic aftereffect phenomena. The aftereffects under double-field were calculated, and the condition under which the time dependence of magnetization was non-monotonic was given.
Preisach model, Magnetic aftereffect, Fluctuation field, Activation volume
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【期刊论文】Oxygen vacancy enhanced the room temperature ferromagnetism in Ni-doped TiO2 thin films
侯登录, D.L. Hou, H.J. Meng, L.Y. Jia, X.J. Ye, H.J. Zhou, X.L. Li
Physics Letters A 364 (2007) 318-322,-0001,():
-1年11月30日
Ni-doped TiO2 anatase thin films were fabricated by reactive magnetron sputtering on SiO2 substrates. The doping and annealing effects on structure and magnetism for the films have been systematically investigated. The results show that ferromagnetism originated from the doped matrix and enhancement (suppression) of ferromagnetism is strongly correlated with the increase (decrease) of oxygen vacancies in TiO2.
Diluted magnetic semiconductors, Room-temperature ferromagnetism, Oxygen vacancy, Magnetic domains
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侯登录, G. D. Tang, D. L. Hou, W. Chen, X. Zhao, W. H. Qi
APPLIED PHYSICS LETTERS 90, 144101 (2007),-0001,():
-1年11月30日
A quantum-mechanical potential barrier model for estimating the number ratio between different valence cations in multiatom compounds is proposed. It is supposed that there is a potential barrier between a cation-anion pair. The height of the potential barrier is proportional to the ionization energy of the cation, and the width of the potential barrier is related to the distance between neighboring cations and anions. As examples for using this model, the distribution of cations with different valences in some ABO3 lanthanum manganites is explained satisfactorily.
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【期刊论文】Magnetic properties of Mn-doped ZnO powder and thin films
侯登录, Deng-Lu Hou, Xiao-Juan Ye, Huai-Juan Meng, Hong-Juan Zhou, Xiu-Ling Li, Cong-Mian Zhen, Gui-De Tang
Materials Science and Engineering B 138 (2007) 184-188,-0001,():
-1年11月30日
Zno.96Mn0.04O powder and thin films were prepared by standard solid-state reaction processes and radio-frequency (RF) magnetron sputtering. Magnetic measurements indicate that the powder is paramagnetic for temperatures above 3K, while the thin films annealed in vacuum are ferromagnetic at room temperature with a transition temperature of about 400K. The largest saturated magnetization (Ms) was found to be about 1.05
Diluted magnetic semiconductor, Ferromagnetism, Sputtering
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【期刊论文】Magnetic properties of n-type Cu-doped ZnO thin films
侯登录, D. L. Hou, X. J. Ye, H. J. Meng, H. J. Zhou, X. L. Li, C. M. Zhen, G. D. Tang
APPLIED PHYSICS LETTERS 90, 142502 (2007),-0001,():
-1年11月30日
A series of n-type Zn1-xCuxO (x = 0.02, 0.06, 0.10, and 0.12) films was prepared using direct current reactive magnetron sputtering. Magnetic measurements indicate that all the films are ferromagnetic at room temperature and the moment per Cu ion decreases with increasing copper concentration and nitrogen doping. The observed magnetic moment was 1.8
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