Studies On Magnetoresistance In Fe/In/Fe Trilayers

An electron is the carrier of both "charge" and "spin". With the dawn of the new millennium has emerged a novel technology, which exploits electron spin and uses it to differentiate electrical carriers into two different types according to their spin directions. As the spin-electronics (spintronics) devices such as magnetic hard disk drive (HDD), spin transistor and magnetic random access memory (MRAM) were commercial used or developed as prototypes, spintronics becomes one of the most rapidly expanding fields in basic research and industrial application.Magnetic sandwich with two ferromagnetic layers (FM) separated by a nonferromangtic layer (NFM), is the key element of the spin-electronics (spintronics) devices. Although the GMR effect has researched in many metal sandwiches, the study of the new GMR material is valued not only in science but also in application.In this paper, the development and mechanism of several kinds of magnetoresistance effect presented generally and briefly. Based on this, the principles, equipments, methods and processes of the preparation and characterization of series Fe/In/Fe trilayers are introduced. The results of an extensive study of conduction mechanism and their magnetic properties in such Fe/In/Fe trilayers are presented.In short, the main works and results of the dissertation are as follows:(1) Fe/In/Fe trilayers were grown by ion beam sputtering for ferromagnetic layers and dc magnetic sputtering for nonferromagnetic layer on well cleaned glass substrates at room temperature.(2) GMR and AMR are observed in sputtered Fe (12.0 nm)/In (t nm)/Fe (12.0 nm) trilayers. We observe the GMR with a maximum of -0.38 % at 20 K for sample with In thickness 1.05 nm. The GMR mainly arises from the AFM coupled magnetization.(3) The GMR effect is composed of the low-field MR and the high-field MR. The low-field MR, which corresponds to ferromagnetic contribution MR_FM. The high-field MR mainly corresponds to superparamagnetic effect at the intermixed Fe/In interface.(4) The GMR is near constant at low temperature, and temperature decreases linearly with increasing temperature at high temperature, which is ascribed to the interplay between spin-dependent electro-phonon scattering and spin-mixing electron-magnon scattering.