Zn_xFe_(3-x)O_4-α-Fe_2O_3纳米多晶材料中的隧道磁电阻效应与微结构(英文)

Microstructures and TMR properties of nano polycrystalline Zn_xFe_(3-x(O_4 with α-Fe _2O_3 grain boundaries

在具有纳米绝缘层的多晶锌铁氧体体系中 ,当晶界为α Fe2 O3纳米量级的绝缘层时 ,则构成 (ZnxFe3 xO4) α Fe2 O3非均匀体 ,电子显微分析证实了这种微结构。该体系在 0 5T磁场、4 2K温度下 ,磁电阻效应可达 1 2 80 %,30 0K下为 1 58%

Giant tunneling magnetoresistance (TMR) effect as large as 1280% at 4 2K and 158% at 300K was observed in Zn 0 41 Fe 2 59 O 4 α Fe 2O 3 nano polystalline sample. The Zn 0 41 Fe 2 59 O 4 grains are separated by insulating α Fe 2O 3 thin layer boundaries with several nm thickness. The microstructures have been verified by TEM and SAED as well as HREM. The huge TMR is attributed to the high spin polarization Zn 0 41 Fe 2 59 O 4 grains and antiferro\|magnetic correlation between magnetic domains on both sides of the insulating α Fe 2O 3 boundary. The Zn 0 41 Fe 2 59 O 4 ferrite is a new type half metallic material with a huge TMR at room temperature, which is interesting to be further studied in the future.