Title

Investigation Of The Structural And Magnetic Properties Of Thin Ferromagnetic Films

Date

1963

Index Abstract

Contrails and DTIC truncated

Photo Quality

Incomplete

Report Number

WADD TR 60-787 Part II

Creator

Baltz, A.

Doyle, William

Corporate Author

Franklin Institute

Laboratory

Directorate of Materials and Processes

Extent

65

Identifier

AD0403892

AD0403892

Access Rights

OTS

Distribution Classification

1

Contract

AF 33(616)-6298

DoD Project

7371

DoD Task

727103

DTIC Record Exists

Yes

Distribution Change Authority Correspondence

None

Report Availability

Full text available by request

Date Issued

1963-03

Abstract

Permalloy films evaporated at normal and oblique incidence to a substrate were examined by replication of their surfaces. Electron micrographs revealed chains of particles perpendicular to the incident beam when the angle of incidence was 70 ° degrees. The degree of alignment depended upon the angle of incidence and thickness of the film. A statistical analysis of the micrographs was made.


Permalloy films were epitaxially grown on NaCl and were annealed by electron bombardment in an electron microscope. Perfect single crystal diffraction patterns indicated the presence of [100] parent crystals and [122] twin crystals. Fringe patterns observed on electron micrographs were identified by dark field microscopy and electron diffraction as being caused by platelets of twins 100-400 Å thick, lying parallel to {111} planes of the parent crystal. The non-integral reflections were shown to be caused by double diffraction.

The angular dependence of the torque in Permalloy films has been studied. In films with hc, the ratio of coercive force to anisotropy field, less than 0.5, the results agree very well with the formulas for magnetization reversal in an infinite cylinder. When hc>0.5, the situation appears very complex. The unidirectional hysteresis observed in this range can be understood very well if the existence of regions with negative anisotropy is assumed. Various methods of determining the anisotropy have been compared and a torque technique for measuring dispersion in both magnitude and direction developed. The anisotropy found in films as a function of the angle of incidence of the evaporation beam and the anisotropy in epitaxially grown films is reported. Finally the use of a vibrating sample magnetometer to determine the hysteretic properties of thin films is discussed

Publisher

Wright-Patterson Air Force Base, OH : Directorate of Materials and Processes, Aeronautical Systems Division, Air Force Systems Command

Distribution Conflict

No

Type

report

Provenance

Lockheed Martin Missiles & Fire Control

Subject

Magnetic Properties

Ferromagnetic Materials

Thin Film Storage Devices

Vacuum

Carbon

Electrons

Oxides

Nickel

Platinum Alloys

Palladium Alloys

Chromium

Evaporation

Rotation

Hysteresis

Torque

Format

65 pages ; cm.