The Preparation And Mechanism Of The Film About Organic Magnetic Resistance

In recent years, the study on the magnetoresistance effect research from inorganicmaterials to organic materials.New research shows that the magnetic resistivity of organicmaterial is more than10%,which is in room temperature and low magnetic field (~10mT),over the same condition of inorganic nonmagnetic materials. The preparation of organicsemiconductor is much simpler than inorganic semiconductor. For example,smallmolecular semiconductor film and polymer semiconductor film can be made respectively invacuum deposition method and spin coating, ink jet printing,leading to the cost can begreatly reduced. Organic magnetoresistance effect does not depend on the direction ofmagnetic field, room temperature and low field. The characteristic provides theoryfoundation for the realization of the optical, electrical and magnetic integration device, andwill play a great role in the field of computer, energy, optical communication and sensingtechnology.The theory is the hot topic in the solid state electronics emerges and has importantscientific significance.The research result of organic magnetoresistance films, technologyand materials is expected to be used in Magnetic Random Access Memories (MRAM),flexible touched screen products and so on, so it has a profound application significance.Polyvinyl carbazole/8-hydroxyquinoline aluminum composite films with differentprocess conditions were prepared on ITO substrate through spin-coating method. We useMeasurement System Profiler to measure the thickness of the sample.Thickness of filmaffects the transport of carrier in the film, affecting the resistance directly. We test thesurface appearance and the roughness of the sample by Atomic Force Microscope, whichdirectly affects the tranport of the carrier. We measure the resistivity of thin films throughfour point probe assembly and high precision resistance measuring instrument.Results show that the hyperfine effect between the two molecules is strong,whenmass ratio is4:1. The spin of carrier is affected by magnetic field,and then there is anincrease in the formation probability of polaron and singlet exciton in composite films. Theincrease in the formation probability leads to the adding of the carrier mobility in the thinfilm,which results in negative magnetoresistance effect of the thin film;the composite film is uniform,when the thickness of the film is221.3nm,which increases the carrier mobility;the defects of the film are improve by the heating temperature of60℃.We get the bestmagnetic resistance rate of30.58%.