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Large low-field tunneling magnetoresistance of CrO2/(CrO2∕Cr2O3) powder compact with two coercivities, A

Wang, Jingping
Che, Ping
Feng, Jing
Lu, Minfeng
Liu, Jianfen
Meng, Jian
Hong, Yuanjia
Tang, Jinke
Two channels of the conductance G exist in cold-pressed powder compacts of CrO2/(CrO2/Cr2O3), where two types of granules have different coercivities. One of the channels is the spin-dependent intergranular tunneling conductance, and the other one is the spin-independent higher-order inelastic hopping conductance. The conductance is mainly related with the spin-dependent tunneling channel at low temperature. A large low field tunneling magnetoresistance (TMR) of 30.4% is achieved in 950 Oe field at 2 K. The reason is the relative orientation of the magnetization that tends to be antiparallel between the two coercivities. Field dependence of the tunneling magnetoresistance shows two better-separated peaks than that of CrO2 powder compact. The results suggest that the introduction of CrO2/Cr2O3 improves low field sensitivity, TMR, and switching characteristics.
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University of Wyoming. Libraries