BZT-BCT基复合薄膜磁电存储单元及其电致磁电效应研究

项目名称： BZT-BCT基复合薄膜磁电存储单元及其电致磁电效应研究

项目编号： No.51502204

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 一般工业技术

项目作者： 韩叶梅

作者单位： 天津理工大学

项目金额： 20万元

中文摘要： 基于应力/应变调制机理，采用具有大压电系数的0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.3Ca0.7)TiO3(0.5BZT-0.5BCT)作为铁电层，Fe70Ga30薄膜为铁磁层，制备一种具有大电致磁电效应的环境友好型磁电存储器件。在此基础上，提出铁电层采用“菱方晶相 (1-x)BZT-xBCT/四方晶相(1-y)BZT-yBCT”的双铁电层结构，以克服基底电极对电畴运动的阻碍；铁磁层用微米尺寸的Fe70Ga30薄膜以减小多个磁畴运动的宏观平均，实现铁电/铁磁结构存储器单元。用非线性热力学模型模拟分析双铁电层的层间和畴间的机电耦合，研究双铁电层结构的压电增强效应。根据热力学唯象理论，分析电场诱导的铁电畴的旋转和畴壁运动与磁化翻转之间的关系，研究电致磁电效应的微观机制。将获得能够利用电场直接写入信息数据，利用磁电阻的变化读取信息的电写/磁读式磁电存储器单元。国内外未见报道。

中文关键词： 磁电复合薄膜；磁电耦合效应；磁电存储器；电致伸缩；磁致伸缩

英文摘要： The appeal of magnetoelectric memory(MERAM), is that it combines the advantages of.ferroelectric RAM (FeRAM), such as quick and low-power writing, and magnetic RAM.(MRAM), such as non-volitility and easy read-out of the state, and eliminates either of their individual disadvantages (destructive reading of the state and high-energy writing). In this research, we will develop a novel approach to MRAM cell based on magnetoelectric coupling effect. 0.5BZT-0.5BCT film and Fe70Ga30 will be used to prepare magnetoelectric memory cell. Further, (1-x)BZT-xBCT (Rhombohedral)/ (1-y)BZT-yBCT (Tetragonal) bilayers (piezoelectric) and micron sized ferromagnetic Fe70Ga30 (magnetostrictive) film pad will be employed in the fabrication of the memory cell. BZT-BCT bilayers combined with small Fe70Ga30 square pads will be used to overcome the clamping effect from the substrate and the average effect of the domain movement therefore enhance the interlayer and interdomain coupling effect. Mechanical transduction couples the strain to the Fe70Ga30 layer, which then changes its magnetic anisotropy and thus the magnetoresistance. We will use nonlinear thermodynamics to analyze the enchanced piezoelectric effect in the ferroelectric BZT-BCT bilayers consisting of tetragonal (T) (1-y)BZT-yBCT and rhombohedral (R) (1-x)BZT-xBCT films. Mechanisms of the electric field control of magnetization and magnetoresistance will be analyzed. Using this electric field control of ferromagnetism and thus the magnetoresistance state, the demonstration of electric-write / magnetic-read magnetoelectric memory cell will be presented.

英文关键词： magnetoelectric composite film;magnetoelectric coupling;magnetoelectric memory;electrostriction;magnetostriction