Language：Japanese   Publisher：The Magnetics Society of Japan  

We attempted to deposit a hexagonal barium ferrite (BaM) film with a thickness of less than 50 nm by using an alternate periodic atomic layer deposition method. BaM films from 11.5 to 115 nm thick were deposited at 630°C on a ZnFe₂O₄ (20nm) underlayer of (111) texture. Compared with films deposited by conventional sputtering, the film obtained in this study had excellent c-axis orientation and crystallinity. Even the BaM film with a thickness of 11.5 nm had clear X-ray diffraction peaks from the BaM c-plane. The crystallite size of the film decreased significantly as the thickness of the BaM layer decreased, and the typical crystallite size of the 11.5-nm-thick film was about 25 nm. The coercive force of the film in the perpendicular direction, however, decreased markedly as the thickness of the BaM layer decreased below 23 nm. A magnetic intermediate layer was produced in the film between the BaM layer and ZnFe₂O₄ underlayer, and thus the film had a double layer structure composed of a BaM layer with perpendicular magnetization and an intermediate layer with an in-plane magnetization.

DOI： 10.3379/jmsjmag.23.1209

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Language：English   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

We developed a new sputter deposition technique called sputter beam deposition (SBD) in which both the kinetic energy and the distribution of incident angles of the deposition particles are controlled. In this study, Ti films with hcp structure were deposited by both SBD and conventional de magnetron sputtering. The crystal orientation of the film depended considerably on the kinetic energy of the depositing atoms. Film with c-axis orientation was obtained when most of the depositing atoms had energy below 1 eV, whereas film with hcp (100) orientation was obtained when most of them had energy above 1 eV, The distribution of the incident angles in SBD depended little on the sputtering gas pressure and had a similar distribution to that observed at a low gas pressure. The film deposited by SBD had much smoother surface than the film deposited by conventional magnetron sputtering. (C) 1999 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0013-4686(99)00103-6

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Language：English   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Sputter deposition of nickel films at liquid nitrogen temperature was performed to clarify the effects of the surface migration of the deposited atoms. The film deposited at liquid nitrogen temperature and low Ar gas pressure had excellent (111) orientation and good crystallinity. Therefore, deposition at a low-temperature and low Ar gas pressure is a useful technique for obtaining film with excellent crystal orientation of the closest packing plane. Ion bombardment of the film surface during deposition at liquid nitrogen temperature led to a large degradation of the film crystallinity, but it had quite the opposite effect at room temperature, i.e., it promoted the (111) orientation of the film and improved the crystallinity of the film. These results indicate that the ion bombardment produced defects in the crystallites at a low temperature where migration of the deposited atoms was limited. (C) 1999 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0013-4686(99)00101-2

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Language：English   Publisher：ELSEVIER SCIENCE BV  

Sputter-deposition of c-axis perpendicularly oriented hexagonal barium ferrite (BaM: BaFe12O19, and BaW: BaFe18O27) thin films was attempted by means of an alternate periodic deposition of Fe3O4 layer (S-layer) and BaFe6O11 layer (R-layer). BaM film with c-axis orientation was obtained at temperatures above 540 degrees C, in which control of the thickness of both S-layer and R-layer was very important to obtain a BaM thin film with c-axis orientation. BaW film, however, was not obtained at the periodic layer deposition condition corresponding to the BaW crystal (S-layer = 9.3 Angstrom, R-layer = 6.9 Angstrom). (C) 1998 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0304-8853(97)00981-5

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Language：Japanese   Publisher：The Magnetics Society of Japan  

In order to obtain a hexagonal barium ferrite (BaM) film with large saturation magnetization, we attempted to reduce the thickness of a ZnO underlayer and to deposit BaM film on underlayers of various materials such as α-Fe₂O₃, amorphous barium ferrite (a-BaM), amorphous BaFe₆O₁₀ (a-BaFe₆O₁₀), and ZnFe₂O₄. The following results were obtained: (1) A ZnO underlayer less than 10 nm thick significantly degraded the <i>c</i>-axis orientation of the BaM films. (2) A BaM film with <i>c</i>-axis orientation was obtained only on ZnO, a-BaM/ZnO, and ZnFe₂O₄ underlayers. In particular, a film deposited on a (111)-oriented ZnFe₂O₄ underlayer had excellent <i>c</i>-axis orientation and magnetic properties. (3) The saturation magnetizations of films deposited on the various underlayers had low values below 260 emu/cc, and could not be increased by reducing the thickness of the ZnO underlayer or by depositing the film on an underlayer that did not contain ZnO.

DOI： 10.3379/jmsjmag.22.481

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Language：Japanese   Publisher：The Magnetics Society of Japan  

In order to obtain a hexagonal barium ferrite (BaM) film with large saturation magnetization, we attempted to reduce the thickness of a ZnO underlayer and to deposit BaM film on underlayers of various materials such as α-Fe₂O₃, amorphous barium ferrite (a-BaM), amorphous BaFe₆O₁₀ (a-BaFe₆O₁₀), and ZnFe₂O₄. The following results were obtained: (1) A ZnO underlayer less than 10 nm thick significantly degraded the <i>c</i>-axis orientation of the BaM films. (2) A BaM film with <i>c</i>-axis orientation was obtained only on ZnO, a-BaM/ZnO, and ZnFe₂O₄ underlayers. In particular, a film deposited on a (111)-oriented ZnFe₂O₄ underlayer had excellent <i>c</i>-axis orientation and magnetic properties. (3) The saturation magnetizations of films deposited on the various underlayers had low values below 260 emu/cc, and could not be increased by reducing the thickness of the ZnO underlayer or by depositing the film on an underlayer that did not contain ZnO.

DOI： 10.3379/jmsjmag.22.481

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Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10463881

Language：English   Publisher：The Magnetics Society of Japan  

&nbsp;&nbsp;A deposition of <i>c</i>-axis oriented hexagonal barium ferrite thin films was attempted by means of an alternate periodic deposition of <i>S</i> (Fe₂O₃) and <i>R</i>(BaFe₆O₁₀) layers. All of the films obtained in this study had (001) texture, although they also contained a spinel phase with (111) orientation. Crystallite size in the film depends on the ratio of the thickness of the <i>S</i> layer to that of the <i>R</i> layer, and increased as this ratio increased. M-type barium ferrite (BaM) thin films with excellent c-axis orientation were obtained when the thickness of the <i>S</i> and <i>R</i> layers were 4.7 &Aring; and 6.9 &Aring;, respectively. We also tried to form the W-type barium ferrite (BaW) film by depositing <i>S</i> layers 9.3 &Aring; thick and <i>R</i> layers 6.9 &Aring; thick altemately. The film, however, did not contain the BaW crystallites and was a mixture of BaM and the spinel-type crystallites.

DOI： 10.3379/jmsjmag.22.S1_188

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Language：English   Publisher：AMER INST PHYSICS  

Deposition of c-axis perpendicularly oriented barium ferrite (BaM:BaFe12O19) thin films was attempted by means of an alternate periodic deposition of S (spinel Fe3O4) and R (BaO . 3Fe(2)O(3)) layers. The period of the layers was fixed at 1.15 nm, which corresponds to the period of hexagonal barium ferrite crystals in the c-axis direction. Films 115 nm thick were deposited on a c-axis oriented ZnO underlayer by using a dc sputtering system with three facing target sputtering sources. This layer deposition method was expected to deposit a film with much better crystallite orientation at a lower substrate temperature than needed to deposit a film when using a conventional sputter deposition method (i.e., sputter deposition using a stoichiometric BaM sintered target). The films deposited at temperatures above 540 degrees C had a hexagonal crystal structure and showed c-axis orientation, but this deposition method did not result in a marked reduction of substrate temperature needed for the deposition of a BaM film with hexagonal crystal structure. The films deposited at 650 degrees C had a clear terraced surface due to the growth of disk shaped hexagonal crystallites. The saturation magnetization of the film was about 220 emu/cc and the coercive force of the films was about 2.2 kOe. (C) 1997 American Institute of Physics.

DOI： 10.1063/1.365528

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