微量Al^(3+)掺杂对钴铁氧体磁和电性能的影响

Enhanced Magnetic and Electrical Properties in Cobalt Ferrite Ceramics by Doping Trace Amount of Aluminum

采用固相反应法,制备了Al3+掺杂的钴铁氧体CoFe2xAlxO4(x=0.000,0.012,0.023,0.035,0.069,0.092)系列样品。从XRD的结果分析,钴铁氧体磁性离子间跃迁距离随x的增加而降低,表明Al3+掺杂进入了尖晶石晶格,拉曼光谱的结果验证了这一结论。当x≤0.069,随着x的增大,钴铁氧体直流电阻率增加约2个数量级;当x>0.069,直流电阻率开始下降。微量Al3+掺杂后钴铁氧体的矫顽力略有降低,但饱和磁化强度增加。最大磁致伸缩量比未掺杂Al3+的低,但磁致伸缩系数增加。

Al-doped cobalt ferrites (CoFe2xAlxO4 , x = 0, 0.012, 0.023, 0.035, 0.069, and 0.092) have been synthesized by the solid phase reaction method. The effects of Al 3+ ions on structural, magnetic properties and DC electrical resistivity were investigated. From the analysis of X-ray diffraction patterns, Al has been doped into the spinal crystal lattice, for the hopping distance between magnetic ions decreases with the Al doping amount (x) increasing. The magnetic and electrical properties have been studied as a function of the dosage of Al. It is observed that DC electrical resistivity increases up to around two magnitude with increasing aluminum doping amount when x ≤0.069, but then drops sharply when x>0.069. The magnetic coercivity of cobalt ferrite decreases after Al doping, whereas the saturation magnetization increases with Al doping. The maximum magnetostrictin (λ) for aluminum doped samples is lower than un-doped cobalt ferrite but the sensitivity of strain to applied magnetic field (dλ/dH) is strengthened.