压力对钙钛矿氧化物NiCrO3物理特性的影响
时间:2018-03-13 15:45 来源:毕业论文 作者:毕业论文 点击:次
| 摘要本文以NiCrO3为研究对象，采用密度泛函理论，从理论上系统研究了压力对其几何结构、电子自旋特性、能带结构、磁学特性、居里温度等的影响，通过对反铁磁钙钛矿氧化物NiCrO3施加静水压力，成功调制得到了具有半金属特性的NiCrO3。当压力高于80GPa时，NiCrO3由常压下的反铁磁半导体转变为反铁磁半金属，自旋向上子带的能隙由3.9eV减至2.5eV；自旋向下子带的能隙由0.35eV减为零。Ni，Cr和O离子的磁矩在施加的压力范围内只有细微的变化，同时，Ni和Cr离子均呈现为高自旋态。反铁磁半导体NiCrO3的奈尔温度随着压力的增加将从270K逐渐上升，并在压力为60GPa左右时，达到最大值321K；而反铁磁半金属NiCrO3奈尔温度大约为309K。本毕业论文的研究成果为压力环境下材料器件的使用、压力对材料物理性质的影响以及通过压力有效调控材料的物理性质提供有力的理论指导。19583 关键词 钙钛矿氧化物 NiCrO3 几何结构 电磁学性质 压力 毕业论文设计说明书（论文）外文摘要 Title Pressure effects on the physical properties Of perovskite oxides of NiCrO3。 Abstract In this paper, NiCrO3 for the study, using density functional theory , system theory to study the pressure on its geometry , electron spin characteristics , band structure , the impact of magnetic properties , Curie temperature, etc. , by antiferromagnetic perovskite oxide NiCrO3 hydrostatic pressure applied successfully got NiCrO3 modulation with half-metallic properties. When the pressure is higher than 80GPa, NiCrO3 by the antiferromagnetic semiconductors under pressure into a half-metallic antiferromagnetic , spin-up sub-band energy gap from 3.9eV down to 2.5eV; spin-down sub-band energy gap by 0.35eV reduced to zero . Ni, Cr , and only minor changes in the magnetic moment of O ions exert pressure range , while , Ni and Cr ions are rendered as high-spin state . Nair antiferromagnetic semiconductor with increasing temperature NiCrO3 pressure gradually increased from 270K and a pressure of about 60GPa , the maximum 321K; the half-metallic antiferromagnetic NiCrO3 Nair temperature of about 309K. Results of this study for the use of the material of the device under pressure , the effect of pressure on the physical properties of materials as well as through the effective regulation of the pressure of the physical properties of the material to provide theoretical guidance . In this paper, NiCrO3 for the study, using density functional theory , system theory to study the pressure on its geometry , electron spin characteristics , band structure , the impact of magnetic properties , Curie temperature, etc. , by antiferromagnetic perovskite oxide NiCrO3 hydrostatic pressure applied successfully got NiCrO3 modulation with half-metallic properties. When the pressure is higher than 80GPa, NiCrO3 by the antiferromagnetic semiconductors under pressure into a half-metallic antiferromagnetic , spin-up sub-band energy gap from 3.9eV down to 2.5eV; spin-down sub-band energy gap by 0.35eV reduced to zero . Ni, Cr , and only minor changes in the magnetic moment of O ions exert pressure range , while , Ni and Cr ions are rendered as high-spin state . Nair antiferromagnetic semiconductor with increasing temperature NiCrO3 pressure gradually increased from 270K and a pressure of about 60GPa , the maximum 321K; the half-metallic antiferromagnetic NiCrO3 Nair temperature of about 309K. Results of this study for the use of the material of the device under pressure , the effect of pressure on the physical properties of materials as well as through the effective regulation of the pressure of the physical properties of the material to provide theoretical guidance. Keywords Perovskite NiCrO3 Structural property Electronic structrue pressure (责任编辑：qin) |