Interplane Tunneling Magnetoresistance in a Layered Manganite Crystal
The current-perpendicular-to-plane magnetoresistance (CPP-MR) has been investigated for the layered manganite, La2-2xSr1+2xMn2O7 (x = 0.3), which is composed of the ferromagnetic-metallic MnO2 bilayers separated by nonmagnetic insulating block layers. The CPP-MR is extremely large (10(4) percent at 50 kilo-oersted) at temperatures near above the three-dimensional ordering temperature (Tc approximately 90 kelvin) because of the field-induced coherent motion between planes of the spin-polarized electrons. Below Tc, the interplane magnetic domain boundary on the insulating block layer serves as the charge-transport barrier, but it can be removed by a low saturation field, which gives rise to the low-field tunneling MR as large as 240 percent.
Kimura
T
T. Kimura, Y. Tomioka, H. Kuwahara, A. Asamitsu, M. Tamura, Joint Research Center for Atom Technology (JRCAT), Tsukuba, 305, Japan. Y. Tokura, JRCAT, Tsukuba, 305, Japan, and Department of Applied Physics, University of Tokyo, Tokyo 113, Japan.
Tomioka
Y
Kuwahara
H
Asamitsu
A
Tamura
M
Tokura
Y