Measurement of the Crystalline Anisotropy Constant of Titanomagnetite

钛磁铁矿晶体各向异性常数的测定

• 批准号: 8803417
• 负责人: Guy Smith
• 金额: $ 4.51万
• 依托单位: Saint Louis University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-12-15 至 1992-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8803417&HistoricalAwards=false
• 关键词: Measurement; Crystalline; Anisotropy; Constant; Titanomagnetite

Magnetocrystalline anisotropy and magnetostriction are fundamental properties of magnetic materials and derive from the fact that the exchange energy which is responsible for the existence of spontaneous magnetization is controlled by the overlap of electron clouds in the crystal. Magnetocrystalline anisotropy derives from the fact that the energy of magnetization is a function of the orientation with respect to the lattice. This leads to "easy" and "hard" directions for magnetization and is a critical parameter controlling the width of domain walls. It is thus clearly important that we have accurate measurements of these parameters if we are to make much progress in our understanding of TRM mechanisms. A major problem is that both constants are known to vary with temperature. In particular, we need values at temperatures near the Curie point as this is where remanence in locked in. The PI will make sure measurements. He will measure both constants for x-values up to 0.8 and temperatures up to the Curie point. His goal is to measure the magnetocrystalline anisotropy constant for several x-values and at temperatures significantly above room temperature. He will use a technique that has seen only limited use in rock magnetism, ferromagnetic resonance.

磁晶各向异性和磁致伸缩是磁性材料的基本性质，它们源于晶体中电子云的重叠控制着自发磁化存在的交换能。磁晶的各向异性源于磁化能是晶格取向的函数。这导致磁化的“易”和“硬”方向，是控制畴壁宽度的关键参数。因此，如果我们要在理解TRM机制方面取得很大进展，那么对这些参数进行精确测量显然是很重要的。一个主要问题是，已知这两个常数都随温度变化。特别是，我们需要居里点附近的温度值，因为这是剩余物被锁定的地方。PI将确保测量。他将测量x值至0.8的常数和居里点以下的温度。他的目标是在明显高于室温的温度下测量几个x值的磁晶各向异性常数。他将使用一种在岩石磁学中应用有限的技术——铁磁共振。