The Magnetoresistance Properties And Characterization Of NiFe Films

The application of NiFe film play a very important role in the magnetic field. Itsmagnetoresistance have directivity make it have a broad application in earthmagnetism navigation field. It also have a broad application in production of sensorand head because it has a small magnetic saturation field and a high magnetic fieldsensitivity. In this paper, the AMR value and magnetic performance of NiFe films areimproved to meet the practical demand for magnetic material. A series ofTa(3nm)/NiO(T)/NiFe(I)/NiO(2nm)/NiFe(20nm)/NiO(2nm)/NiFe(I)/NiO(T)/Ta(4nm),Cu(7nm)/Ni81Fe19(10nm)/Cu(x)/Ni81Fe19(10nm)/NiO(25nm)/Cu(4nm),Ta(7nm)/Ni81Fe19(10nm)/Ta(y)/Ni81Fe19(10nm)/NiO(25nm)/Ta(4nm),(Ni81Fe19)80.7Nb19.3(2nm)/Ni81Fe19(10nm)/Nb(z)/Ni81Fe19(10nm)/NiO(25nm)/Nb(3nm) were prepared underappropriate conditions. The effect of that NiFe was inserted into oxidationintercalation for the AMR value of NiFe films are studied at required processcondition. At the same time, the effects of different isolating course material withdifferent thickness for the AMR value of NiFe films are studied.The AMR value andhysteresis hoop of Ni81Fe19films were measured by four point probe technology andvibrating sample magnetometer (VSM) respectively. We analysis the experimentalresults and observe the following conclusions:(1) A little NiFe which are inserted into NiO have a great influence on the AMRvalue of NiFe film under high temperature conditions. With the NiFe(I) thicknessincreasing,the AMR value of NiFe film firstly increase and then reduce for Ta(3nm)/NiO(2nm)/NiFe(I)/NiO(2nm)/NiFe(20nm)/NiO(2nm)/NiFe(I)/NiO(2nm)/Ta(4nm).When the NiFe thickness is1nm, the AMR value of the film can reach4.32%andenhance72%comparing with oxide inserting layer. When the NiFe(I) thickness is1nm, NiO(T) thickness have a great influence on the AMR value of NiFe film.With theNiO（T）thickness increasing,the AMR value of NiFe film firstly increase and thenreduce for Ta(3nm)/NiO(T)/NiFe(1nm)/NiO(2nm)/NiFe(20nm)/NiO(2nm)/NiFe(1nm)/NiO(T)/Ta(4nm).When x=4nm, the AMR value of the film can reach4.94%and enhance4.94%comparing with conclusion (1).(2)The spacer layer thickness and different non-magnetic material have an apparentinfluence on the AMR value of NiFe film in the spin valve structure. A series ofCu(7nm)/Ni81Fe19(10nm)/Cu(x)/Ni81Fe19(10nm)/NiO(25nm)/Cu(4nm)、Ta(7nm)/Ni81Fe19(10nm)/Ta(y)/Ni81Fe19(10nm)/NiO(25nm)/Ta(4nm)、(Ni81Fe19)80.7Nb19.3(2nm)/Ni81Fe19(10nm)/Nb(z)/Ni81Fe19(10nm)/NiO(25nm)/Nb(3nm) films are prepared andstudied. The results show that the anisotropic magnetoresistance has a strongdependence on isolating layer thickness. These three different spin valve isolationlayer thickness series which are prepared at450℃correspond to different maximumAMR and sensitivity. The AMR value of the films can be reached to2.8%and thesensitivity is1.1×10-3%m·A-1under the condition which the Cu thickness is1nm asisolation layer. The AMR value of the films can be reached to2.6%and the sensitivityis2.3×10-3%m·A-1under the condition which the Ta thickness is2nm as isolationlayer. The AMR value of the films can be reached to3.2%and the sensitivity is4.9×10-3%m·A-1under the condition which the Nb thickness is1nm as isolation layer.