Investigation of interface orientation and interface mixing in spin valve heterostructures

Author

Joo, Hyun Sung ; Atwater, Harry A.

Author_Institution

Thomas J. Watson Lab. of Appl. Phys., California Inst. of Technol., Pasadena, CA, USA

Volume

31

Issue

6

fYear

1995

fDate

11/1/1995 12:00:00 AM

Firstpage

3946

Lastpage

3948

Abstract

We have investigated magnetoresistance properties of (100) epitaxial, (111) textured and polycrystalline spin valve heterostructures on (100) Si substrates by UHV ion beam sputtering at room temperature. Magnetoresistance was measured as a function of Cu interlayer thickness (t_i) with 10 Å⩽t_i⩽100 Å and the maximum was found at 20 Å in the case of (100) epitaxial spin valves. Highly (111) textured spin valves with heterostructure configurations similar to (100) spin valves were found to have a slightly lower magnetoresistance than (100) heterostructures, but a very similar functional dependence of magnetoresistance on t_i. Interface mixing during the sputtering process by energetic neutral bombardment was found to significantly affect the magnetoresistance. Samples were made under various sputtering conditions (gas pressure, ion beam energy, target and substrate configuration) that could enhance or suppress high energy neutral bombardment of the growing film surface. Samples made under the conditions that suppressed neutral bombardment showed higher magnetoresistance and more abrupt interfaces as confirmed by small angle X-ray diffraction (SAXD) analysis of interface mixing by energetic neutral bombardment during sputter deposition

Keywords

X-ray diffraction; copper; interface structure; ion beam mixing; iron alloys; magnetic epitaxial layers; magnetic multilayers; magnetoresistance; manganese alloys; metallic superlattices; nickel alloys; soft magnetic materials; sputter deposition; texture; vapour phase epitaxial growth; (100) Si substrates; 10 angstrom; 20 angstrom; Cu interlayer thickness; NiFe-Cu-NiFe-FeMn; UHV ion beam sputtering; energetic neutral bombardment; epitaxial layer; interface mixing; interface orientation; magnetoresistance properties; polycrystalline; room temperature; small angle X-ray diffraction; spin valve heterostructures; sputter deposition; textured film; Ion beams; Magnetic analysis; Magnetic properties; Magnetoresistance; Spin valves; Sputtering; Substrates; Temperature measurement; Thickness measurement; X-ray diffraction;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.489825

Filename

489825