Effect of pressure, ageing and in situ annealing on the electrical properties of thin samarium films

✍ Scribed by P.V. Ashrit; M.A. Angadi

• Publisher: Elsevier Science
• Year: 1982
• Tongue: English
• Weight: 225 KB
• Volume: 32
• Category: Article
• ISSN: 0042-207X
• DOI: 10.1016/s0042-207x(82)80004-3

✦ Synopsis

We report on the effect of pressure, ageing and in situ annealing on the electrical resistivity and temperature coefficient of resistance in thin samarium films over the thickness range lOiN A. On annealing at 180°C for 2 h. film resistivity increases for lower thicknesses but remains constant for higher thicknesses. For films grown at higher pressures the resistivity decreases at lower thicknesses (~500 A).

Of late there have been many reports on the effect of deposition parameters on the electrical properties of some of the rare-earth thin films'-lo. It is indeed established that the deposition parameters such as film thicknesslA, substrate temperatures-', substrate materia15, deposition rate5.8.9 and gas absorption'." affect the electrical properties to a great extent. It is also reported that thin rare earth lilms3.' ' , when exposed to air get oxidized and their resistance increases with time. We have already reported on the thickness dependence of the electrical properties of thin samarium lilms"~8 In this letter, we report on the effect ofpressure, ageing and iri sita annealing on the electrical properties of thin samarium films in the thickness range 100-800 A.

Samarium films were deposited by vacuum evaporation (IO-(' torr) of 99.9:" pure samarium (obtained from Leico Industries New York, USA), onto a glass substrate held at room temperature (22°C). Annealing of the film was done in sifts for 2 h, at a pressure of 4 x 10L6 torr and for two different temperatures, 100 and 180°C. To study the efIect of pressure, samarium films of different thickness were grown at a pressure of 10d6 and lOa5 torr. Samarium films were also grown in the oxygen free nitrogen atmosphere at a pressure of 10m5 torr. Other experimental details are given elsewhere".