 |
 |
 |
 |
 |
 |
||
 |
 |
 |
 |
 |
| 5 | 1/1 | 返回列表 |
| 查看: 948 | 回復(fù): 4 | |||
| 當(dāng)前只顯示滿足指定條件的回帖，點(diǎn)擊這里查看本話題的所有回帖 | |||
真的靜奕銅蟲 (初入文壇)
|
[求助]
論文翻譯
|
||
|
Oriented single-crystalline thin films of NiO and Fe304, and Fe304/NiO superlattices have been grown on cleaved and polished substrates of MgO(001), using oxygen-plasma-assisted molecular-beam epitaxy. We report the growth mode and structural characterization of the grown films using in situ reflection high-energy electron diffraction (RHEED) and ex situ scanning electron microscopy and x-ray diffraction. The (001) surface of MgO provides an excellent template for the pseudomorphic growth of these thin films and superlattices, for it has a very small lattice mismatch (0.3-0.9%) to the cubic rocksalt structure of Ni0 and to the half unit-cell dimension of the spinel structure of Fe304. Superlattices consisting of alternating layers of NiO and Fe304 have been grown with a repeat wavelength down to 20 0A (approximately one Fe304 unit cell plus two NiO unit cells) thick. These superlattices exhibit strong crystalline ordering and sharp interface formation. RHEED pattern evolution in situ during growth indicates formation of the rocksalt NiO crystalline symmetry and then the spinel Fe304 crystalline symmetry in a periodic sequence as each material is being deposited. Our data indicate single-phase crystal growth in registry with the substrate, with films of overall cubic symmetry. Strain in the grown films exhibits interesting effects that clearly do not follow a simple elastic model. I. INTRODUCTION Growth of high-quality single-crystalline thin films of metal oxides has become increasingly important recently for both technological and fundamental physical reasons. Ceramic oxides such as the ferrite spinels and magnetic garnets exhibit a rich complexity in magnetic coupling and electronic bonding not found in pure metallic and alloy materials. In addition, because of the strong anioncation bonding in oxides, such films are often tribologically and chemically significant more stable than films with free metal or semiconducting surfaces. Oxide ferrites, especially those in layered structures, can also have superior magnetization and microwave resonance properties for use in a variety of planar device structures and other technological applications. Recently, the synthesis of layered oxide materials has received enhanced notoriety because of the discovery of high-temperature superconductivity in the ceramic perovskite oxides. As a result of this combination of factors, strong research interest deals with issues involved in the growth and integration of magnetic and superconducting oxide structures into planar integrated devices. ' Special emphasis in the research community is being focused on thin films and modulated structures of ferrite materials. ' Magnetic spinels, for example, show great promise in planar device applications because of their superiority as high-density magnetic recording media, their resistance to corrosion and wear, and the inherent advantage non-"lossy" insulating ferrites have in microwave resonant circuits. In addition, layered structures of such ferrite materials allow controllable constraints to be placed on stoichiometry, lattice spacing, and strain that couple directly with their magnetic properties. As a result, layered magnetic oxides are ideally suited to a study of a number of fundamental issues dealing with magnetic coupling, ordering and anisotropy in nonitinerant electron magnetic systems. Using the preparation techniques of molecular-beam epitaxy (MBE), Bando and coworkers have recently grown Fe304 films and Fe304lCoO superlattices, and, using reactive sputtering, Ortiz et al. ' '" have grown Fe304 films and Yoshii et al. ' have grown y-Fe203 films. The current investigation extends these studies and demonstrates the ability to produce constrained metal-oxide thin-film stoichiometries, including modulated structures of highcrystalline order and purity with controllable magnetic ordering and properties. In our work, highly oriented single-crystalline thin films of NiO, Fe304 and Fe30~lNiO superlattices have been grown using oxygen-plasma-assisted MBE. We will discuss here the synthesis and characterization techniques used, with special emphasis on the crystal-growth techniques used and the structural characterization of the resultant films using reflection high-energy electron diffraction (RHEED), scanning electron microscopy (SEM), and x-ray diffraction (XRD). We have found the (001)-oriented surface of MgO single crystals to provide an excellent template for the pseudomorphic growth of both NiO and Fe30~, for it has a small (&1%) lattice mismatch to the cubic rocksalt structure of the former and to the half unit-cell dimension of the spinel structure of the latter. We report the preparation of NiO and Fe304 thin films, as well as superlattices consisting of al-ternating layers of Ni0 and Fe304. The Fe304/NiO superlattices have been grown with modulation wavelength A between 20 and 258 A (the lower limit being slightly greater than one Fe304 unit cell plus two NiO unit cells thick), with optimal crystalline order obtained at substrate growth temperature of 240 C. These films exhibit coherent single-crystalline ordering over several hundred repeat wavelengths. Reported elsewhere in the literature are studies we have made on the magnetization and electron transport properties of these thin films and superlattices' ' which show such effects as an unusually large in-plane versus out-of-plane anisotropy () 10 difFerence) in electron transport as well as strong modulation wavelength-dependent magnetic ordering effects. |
回復(fù)此樓» 猜你喜歡
材料與化工328分調(diào)劑
已經(jīng)有3人回復(fù)
-
279分求調(diào)劑 一志愿211
已經(jīng)有20人回復(fù)
-
293求調(diào)劑
已經(jīng)有3人回復(fù)
-
一志愿華東理工大學(xué)081700，初試分?jǐn)?shù)271
已經(jīng)有6人回復(fù)
-
085404電子信息284分求調(diào)劑
已經(jīng)有3人回復(fù)
-
306求0703調(diào)劑一志愿華中師范
已經(jīng)有9人回復(fù)
-
一志愿吉大化學(xué)322求調(diào)劑
已經(jīng)有6人回復(fù)
-
求調(diào)劑
已經(jīng)有5人回復(fù)
-
344求調(diào)劑
已經(jīng)有3人回復(fù)
-
一志愿哈工大，085400，320，求調(diào)劑
已經(jīng)有3人回復(fù)
丿花落丶小兔
鐵桿木蟲 (知名作家)
- 應(yīng)助: 81 (初中生)
- 金幣: 20021.2
- 散金: 102
- 紅花: 33
- 帖子: 6030
- 在線: 196.5小時(shí)
- 蟲號(hào): 1837819
- 注冊(cè): 2012-05-28
- 性別: MM
- 專業(yè): 電化學(xué)分析
4樓2014-06-04 10:38:27
Paulwolf
榮譽(yù)版主 (文壇精英)
非線性控制領(lǐng)域新人一枚
-
專家經(jīng)驗(yàn): +178 - 翻譯EPI: 23
- 應(yīng)助: 317 (大學(xué)生)
- 貴賓: 4.423
- 金幣: 310300
- 散金: 17942
- 紅花: 554
- 沙發(fā): 3382
- 帖子: 35712
- 在線: 4027.9小時(shí)
- 蟲號(hào): 3131175
- 注冊(cè): 2014-04-12
- 專業(yè): 控制理論與方法
- 管轄: 學(xué)術(shù)會(huì)議
2樓2014-06-03 23:38:31
真的靜奕
銅蟲 (初入文壇)
- 應(yīng)助: 0 (幼兒園)
- 金幣: 71.7
- 帖子: 42
- 在線: 10.7小時(shí)
- 蟲號(hào): 3052161
- 注冊(cè): 2014-03-14
- 性別: GG
- 專業(yè): 基礎(chǔ)物理學(xué)
3樓2014-06-04 08:13:55
| 最具人氣熱帖推薦 [查看全部] | 作者 | 回/看 | 最后發(fā)表 | |
|---|---|---|---|---|
|
[考研] 一志愿哈工大，085400，320，求調(diào)劑 +3 | gdlf9999 2026-03-24 | 3/150 |
|
|---|---|---|---|---|
|
[考研] 341求調(diào)劑(一志愿湖南大學(xué)070300) +5 | 番茄頭--- 2026-03-22 | 6/300 |
|
|
|
[考研] 一志愿重慶大學(xué)085700資源與環(huán)境，總分308求調(diào)劑 +7 | 墨墨漠 2026-03-23 | 8/400 |
|
|
|
[考研] 一志愿武理材料工程348求調(diào)劑 +6 | ￣^￣゜汗 2026-03-19 | 9/450 |
|
|
|
[考研] 316求調(diào)劑 +7 | 梁茜雯 2026-03-19 | 7/350 |
|
|
|
[考研]
 材料與化工考研調(diào)劑
+4
|
孅華 2026-03-22 | 4/200 |
|
|
|
[考研] 070300，一志愿北航320求調(diào)劑 +3 | Jerry0216 2026-03-22 | 5/250 |
|
|
|
[考研] 280分求調(diào)劑 一志愿085802 +4 | PUMPT 2026-03-22 | 7/350 |
|
|
|
[考研] 289材料與化工（085600）B區(qū)求調(diào)劑 +3 | 這么名字咋樣 2026-03-22 | 4/200 |
|
|
|
[考研] 306求調(diào)劑 +5 | 來(lái)好運(yùn)來(lái)來(lái)來(lái) 2026-03-22 | 5/250 |
|
|
|
[考研] 311求調(diào)劑 +3 | 26研0 2026-03-20 | 3/150 |
|
|
|
[基金申請(qǐng)] 山東省面上項(xiàng)目限額評(píng)審 +4 | 石瑞0426 2026-03-19 | 4/200 |
|
|
|
[考研] 280求調(diào)劑 +11 | 咕嚕曉曉 2026-03-18 | 12/600 |
|
|
|
[考研] 材料與化工（0856）304求B區(qū)調(diào)劑 +3 | 邱gl 2026-03-20 | 7/350 |
|
|
|
[考研] 求調(diào)劑 +6 | Mqqqqqq 2026-03-19 | 6/300 |
|
|
|
[考研] 303求調(diào)劑 +5 | 睿08 2026-03-17 | 7/350 |
|
|
|
[考研] 化學(xué)求調(diào)劑 +4 | 臨澤境llllll 2026-03-17 | 5/250 |
|
|
|
[考研] 324分 085600材料化工求調(diào)劑 +4 | llllkkkhh 2026-03-18 | 4/200 |
|
|
|
[考研] 一志愿華南師大 070300（化學(xué)）304分求調(diào)劑 +3 | 0703武芊慧雪304 2026-03-18 | 3/150 |
|
|
|
[考研] 085600材料與化工求調(diào)劑 +6 | 緒幸與子 2026-03-17 | 6/300 |
|