Tunnel Magnetic Resistance Research In Ferromagnet/Organic Semiconductor/Ferromagnet Double Tunnel Junction

With the rapid development of the science and technology, especially electronic semiconductor industry since70s, people’s request of improving the performance of electronic instruments becomes higher and higher. And ferromagnet/organic semiconductor materials become the main topic of the electronic instruments research. The characters of easy synthesis and vast storage are widely used in experiment research.In this dissertation, we research ferromagnet/organic semiconductor/ferromagnet double tunneling magnetic resistance, using Slonczwski free electrons model theory and quantum tunneling method, in which, we see organic semiconductor as square potential barrier and derive the transmission coefficient and tunneling magnetic resistance with the Rashba spin-track coupling effect and the transfer matrix method.When the spin-track coupling strength. KR/K0＝2.0, tunneling magnetic resistance changes with the magnetized deflection angle, if the magnetized deflection angle θ=0, the tunneling magnetic resistance gets minimum value;if θ=π/2, the tunneling magnetic resistance gets maximum value; if θ=π, the tunneling magnetic resistance gets minimum value. When magnetized deflection angle θ=π/6, when KR/K0=0, the tunneling magnetic resistance has maximum value; when KR/K0=1.0, the tunneling magnetic resistance has minimum value;whenKR/KQ=2.0, the tunneling magnetic resistance has maximum value. When magnetized deflection angle θ=π/4, if KR/K0＝0, the tunneling magnetic resistance gets minimum value, and obtains maximum value in KR/K0=2.0;when magnetized deflection angleθ=2π/3, if KR/K0=0, the tunneling magnetic resistance gets maximum value,and obtains minimum value in KR/K0=2.0Due to the nternal electric field effect,when KR/K0=2.0,θ=0,the tunneling maggnetic resistance increases linearly as the increase of the spin polarization rate. When KR/K0=2.0,θ=π,the tunneling magnetic resistance decreases linearly as the increase of the spin polarization rate.When the spin-orbit coupling strength KR/K0=1.5,the voltage pulses E=0.2V, if the angle θ=0,the tunneling magnetic res istance gets a small value and increases along with the increase of the angle,if the angle θ=π/2,the tunneling magnetic resistance gets the maximum value.Whenθ=π.the tunneling magnetic resistance gets the minimum value.When KR/K0=3,θ=π/4,and E=0,the tunneling magnetic resistance gets the minimum value,if E=0.8V the tunneling magnetic resistance gets the maximum value.When KR/K0=3,θ=π/2,and E=0,the tunneling magnetic resistance gets the maximum value,if E=0.8V the tunneling magnetic resistance gets the minimum value.When KR/K0=3,θ=3π/4,and E=0,the tunneling magenetic resistance gets the minimum value,if E=0.8V the tunneling magnetic resistance gets the maximum value.In actual work,because the tunneling magnetic resistance of a magnet/organic semiconductor multilayer film could be influenced by spin polaron,spin coupling strength and the voltage bias,we,therefore, can get different magnetic semiconductor materials by changing any of these factors.