Fe_x-C_(1-x)/Si颗粒膜的巨磁电阻效应

Giant Magnetoresistance of Fe_x-C_(1-x) Films on Si Substrates

利用激光脉冲沉积(PLD)方法制备了沉积于硅基片上的掺杂过渡金属的非晶碳膜结构Fex-C1-x/Si。Fex-C1-x/Si的磁电阻(MR)可正可负,随温度而变化。当温度T<258 K时,Fe0.011-C0.989/Si的MR为负值;当258 K<T<340 K时,该材料的MR为正值,在室温磁场为1 T时,该材料的正MR可以大于20%。且在不同的温度范围中,该材料的MR和外加磁场的依存关系呈现出不同的特点:在T=280和300 K时,当磁场小于1 T时,MR随磁场的增加而快速增加,之后随磁场的继续增加MR增加开始变得缓慢;在T=350 K时,MR近似以磁场的B1.5的规律变化;而在T=30 K时,MR为负值且其大小随磁场的增加而减小。利用双通道模型对该MR效应进行了初步解释。

Fex-C1-x films on n-Si substrates were prepared using pulsed laser deposition method. A novel type of magnetoresistance （MR） was found in Fex- C1-x/Si. When T 〈 258 K, MR of Fe0.011-C0.989/Si is negative and when 258 K 〈 T 〈 340 K, MR is positive. At T = 300 K and B = 1 T a large positive MR of 20% was found in Fe0.011-C0.989/Si. And the MR has different field dependences within the different temperature ranges： MRs at 280 and 300 K are positive and increase rapidly as the magnetic field （B） increases below B = 1 T, and then MR increases slowly as the B increases, whereas MR at 350 K has a B^1.5 of field dependence. Contrary to the above MRs, MR at 30 K is negative and decreases as B increases. A two-channel model was proposed to explain novel MR.