Novel Phenomena in Single-Crystal Oxides

技术摘要人们普遍认为，谁发现和控制了新材料的优化合成，谁就通常控制着对其独特性质的研究，并最终将其成功地整合到先进技术中。建议的研究是在我们最近对4d或5d电子基材料单晶研究的基础上进行的，重点是(1)新型块状-单晶过渡金属氧化物的合成和表征，(2)对新材料的严格探索。我们最近的发现突出了这些材料的新颖性，例如通过避免铁磁状态而获得的轨道驱动的巨磁电阻(CMR)，以及大块单晶中新的自旋阀效应，这是一种微妙的量子现象，依赖于人工薄膜异质结构的精确沉积和纳米图案化，其质量和性能很难控制。虽然这些发现为理解自旋电子学的基本物理开辟了新的途径，并充分发挥了实际设备的潜力，但这些材料特有的新物理--主要由自旋-轨道耦合驱动--仍在不断涌现，更好地理解这种物理肯定会带来新的发现。这就是我们寻求追求的新物理和可能的新发现。技术专长的转移将通过将研究生和博士后直接纳入正在进行的研究工作来实现，目标是在专业期刊上发表成果。拟议中的计划也将构成新成立的先进材料多学科中心的关键推动力。该协会将帮助培养跨学科的专业知识，这将刺激合作研究，并产生协同效应，将吸引新的学生，他们是推动经济的技术领域未来的人力资本。非技术抽象凝聚态物理学致力于识别固体和液体的新的基本性质，这些性质在近几十年来产生了大量尖端技术。人们普遍认为，无论是谁发现和控制了新材料的优化合成，通常都控制着对其独特性质的研究，并最终将其成功地整合到先进技术中。不幸的是，近年来，由于越来越缺乏同时拥有新材料合成和表征技能的科学家，美国在材料研究方面的领导地位已经严重削弱。目前的局势是一个紧迫的国家挑战，如果不加以解决，最终可能会削弱我们的经济竞争力。建议的研究是建立在我们最近在新材料研究方面取得的成功的基础上，并强调块状单晶形式的新材料的合成和表征以及对新材料的严格探索。我们最近的发现突出了这些材料的新颖性，例如大块单晶中新的自旋阀效应，这是一种依赖于精确沉积和人工薄膜异质结纳米图案化的微妙量子现象，其质量和性能很难控制。自旋阀或更一般的自旋电子(磁电子)材料不仅具有作为计算机硬盘驱动器的磁场传感器和读取头的技术潜力，而且还对固体中的磁输运理论提出了根本挑战。这些现象是材料物理和工程学中研究最深入的现象之一，因为它们对每年1000亿美元的电子行业产生了巨大的潜在影响。我们寻求追求的正是这些材料带来的技术潜力和智力挑战。技术专长的转移将通过将研究生和博士后直接纳入正在进行的研究工作来实现，目标是在专业期刊上发表成果。拟议的计划也将成为由NSF EPSCoR RII资助的新成立的先进材料多学科中心的关键推动力。该协会将帮助培养跨学科的专业知识，这将刺激合作研究，并产生协同效应，将吸引新的学生，他们是推动经济的技术领域未来的人力资本。

Technical Abstract It is widely recognized that whoever discovers and controls the optimized synthesis of novel materials generally controls the investigation of their often unique properties and, ultimately, their successful integration into advanced technologies. The proposed research is to build upon our recent success on studies on single crystals of 4d or 5d-electron-based materials and emphasize (1) the synthesis and characterization of novel transition metal oxides in bulk-single-crystal form and (2) a rigorous search for new materials. The novelty of these materials is highlighted by our recent discoveries, such as orbitally-driven colossal magnetoresistance (CMR) attained by avoiding a ferromagnetic state, and a novel spin valve effect in bulk single crystals, a delicate quantum phenomenon that depends upon precision deposition and nanoscale patterning of artificial thin-film heterostructures whose quality and performance are difficult to control. While these discoveries open new avenues for understanding the underlying physics of spintronics, and fully realizing the potential in practical devices, new physics unique to these materials, which are largely driven by spin-orbit coupling, continues to emerge, and better understanding this physics will surely lead to new discoveries. It is this new physics and possible new discoveries we seek to pursue. The transfer of technical expertise will be achieved via direct integration of the graduate students and post-docs into ongoing research efforts with a goal of professional journal publication of results. The proposed program will also constitute a key thrust within the newly established multidisciplinary Center for Advanced Materials. This association will help nurture interdisciplinary expertise that will stimulate collaborative research, and generate synergies that will attract new students who are the future human capital in technologies driving the economy. Non-Technical abstract Condensed matter physics addresses identification of novel, fundamental properties of solids and liquids that have generated a remarkable number of cutting-edge technologies in recent decades. It is widely recognized that whoever discovers and controls the optimized synthesis of novel materials generally controls the investigation of their often unique properties and, ultimately, their successful integration into advanced technologies. Unfortunately, U.S. leadership in materials research has seriously eroded in recent years due to a growing shortage of scientists who possess skills in both the synthesis and characterization of new materials. The current situation presents an urgent national challenge that could ultimately undermine our economic competitiveness if left unaddressed. The proposed research is to build upon our recent success on new materials studies and emphasize the synthesis and characterization of novel materials in bulk-single-crystal form and a rigorous search for new materials. The novelty of these materials is highlighted by our recent discoveries, such as a novel spin valve effect in bulk single crystals, a delicate quantum phenomenon that depends upon precision deposition and nanoscale patterning of artificial thin-film heterostructures whose quality and performance are difficult to control. Spin valves or more generally spintronic (magnetoelectronic) materials not only have technological potential as magnetic field sensors and read-heads for computer hard drives, but also present fundamental challenges to the theory of magnetotransport in solids. These are among the most intensively studied phenomena in materials physics and engineering due to their enormous potential impact on a $100-billion-per-year electronics industry. It is the technological potential and the intellectual challenges these materials present that we seek to pursue. The transfer of technical expertise will be achieved via direct integration of the graduate students and post-docs into ongoing research efforts with a goal of professional journal publication of results. The proposed program will also constitute a key thrust within the newly established multidisciplinary Center for Advanced Materials funded by the NSF EPSCoR RII. This association will help nurture interdisciplinary expertise that will stimulate collaborative research, and generate synergies that will attract new students who are the future human capital in technologies driving the economy.