Studies On The Spin Dependent Transport Properties In Ni₈₀Fe₂₀/ITO Multilayer Thin Films

Spintronics is a new field of electronics, which is not based on conduction by electrons and holes as in microelectronics, but on the different transport properties of majority and minority spin electrons, and it is the spin degree of freedom not the electric charge carries the information. As a basic subject of spintronics, spin dependent transport phenomena has been well studied in both full-metal and metal-inslator systems as multilayers and granular films and new generation of magnetic storage devices has already been developed. It is the hot topic on the spin dependent transport properties in metal-semiconductor systems.In this study of the spin dependent transport properties in Ni₈₀Fe₂₀/ITO trilayer and multilayer thin films, the wide band semiconductor indium tin oxide (ITO), which has been widely used in photoelectronics devices because of its transparent and high conduction and Ni₈₀Fe₂₀ has been employed to form multilayers. The spin dependent transport phenomena in Ni₈₀Fe₂₀/ITO trilayer and multilayer thin films has been studied and the main works are listed as following: (1)A series of Ni8oFe2o/ITO trilayers with same Ni₈₀Fe₂₀ layers and different ITO layers thic-kness were prepared by DC sputtering method on the Si<111> and glass substrates. The magnetic properties were investigated by vibrating sample magnetometer.The magnetic character of the trilayers can be modified by the substrates and the thickness of the ITO layer while the Ni₈₀Fe₂₀ thickness is fixed.(2)A series of[(Ni₈₀Fe₂₀) _tnm/(ITO) _2nm]₂₀ multilayes with same ITO layers and different Ni₈₀Fe₂₀ layers thickness were prepared by DC sputtering method on the Si<111> substrates. The magnetic properties, electrical properties and spin dependent transport properties were investigated by vibrating sample magnetometer and magneto-electronic measurement system.(3) The magnetic character of the trilayers can be modified by the ITO layer while the Ni₈₀Fe₂₀ thickness is fixed.(4)The nonlinear V-I curves is analyzed and it is the tunneling-type behavior which causes the GMR in our multilayer partly.(5)The magnetoresistances(MR) can be manipulated by temperature while the magnetic field and the current are fixed. The positive MR increases to a peak, and then decreased, finally changes to negative MR while the temperature decreases. And the physic process is discussed.(6) The magnetoresistances(MR) can be manipulated by current while the magnetic field and the temperature are fixed. The positive MR changes to negative MR while the current increases at a high temperature; while at a low temperature, the MR is changed to positive MR from negative. And the physic process is discussed.