Studies On The Properties Of SmCo Thin Films Prepared By Pulsed Laser Deposition

SmCo is a new type of rare earth magnetic materials, it has been a research hotspot because of its potential appliccations in magnetic and magneto-optical storage media. It has a high Curie temperature, good corrosion resistance, and consists mainly of the magnetic1:5and2:17phases. With the miniature and portable development needs of equipment and devices, the preparation and properties research of high quality SmCo films are imperative. Long-term researches show that the underlayer materials have great influences on the structure and properties of magnetic films during the process of fabrication of SmCo thin films. Ru, Ta, and Ti buffer layers can effectively reduce the surface roughness of SmCo films and decrease the average grain size of the grains. Therefore, the research of the effects of preparation technics on the structure of SmCo films, as well as the optimization of magnetic and magneto-optical performance has important scientific significance.Tn this article, we prepared SmCo/Cu, SmCo/Cu/Cr and Fe-doped SmCo films on glass and Si(100) substrates by pulsed laser deposition. The film samples contain1:5,2:7and2:17kinds of SmCo phases. We have studied in detail the structure, morphology and magnetic properties of the film samples, and the main research contents are listed below:1. We have studied the impacts of preparation process on the strucuture and properties of SmCo/Cu films. We change the composition of SmCo by regulating Sm contents while Co content is kept constant, and the films show good magnetic anisotropy. We aquired SmCo5film under2x10-4Pa after annealing the sample at620℃when the depositon time of Sm target is6seconds and Co target is3minutes.2. By the introduction of a thin Cr layer under Cu layers, we have studied the optimization fuction of Cr buffer layer to structure, surface morphology and the effects on the magnetic properties of SmCo/Cu thin films. It was found that the Cr buffer layer can effectively decrease the average size of SmCo grains, reduce the surface roughness, improve the crystalline quality of SmCo and enhance the magnetic properties of film samples. We believe that it was due to the refinement of SmCo grains, which was in consistent with results of others. We also studied the impacts of annealing time on the structure and morphology of SmCo films, and the results demostrate that an appropriate extension of the annealing time can drastically improve the crystalline quality for the thick SmCo films.3. We studied the structural variation of Fe/SmCo/Cu films. We found that SmCo2:7phase is suppressed with the increasing of Fe layer thickness and the magneto-optical properties of Fe/SmCo/Cu thin films are enhanced compared with SmCo/Cu films. Substrates can greatly affect the magnetic properties of film samples, and films on Si show better properties than those on glass substrates.4. We also studied high temperature annealing influences on the surface morphology and magnetic properties of Fe/SmCo films. The results have shown that the diffaction peaks of SmCo are enhaced, especially for (001),(002) and (003) lines. We think it is due to the enhancement of Cu (111) peaks after annealing. SEM images show uniform grains and smooth surface after annealing. The magneto-optical properties of both the samples on glass and Si substrates are enhanced after annealing, and the increasement of films on galss substrates is even more sharply.