The epitaxial growth and magnetic analysis of ultrathin films of iron/silver and iron/nickel

Miscellaneous · Fri Jan 01 00:00:00 EST 1993

OSTI ID:7236545

Wieczorek, M D

The first part of these thesis concerns Fe(110)/Ag(111) multilayers, the second investigates the Fe(100)/Ag(100) system and the last examines Fe/bcc Ni multilayers. All films were grown using molecular beam epitaxy, examined for in-plane crystalline structure using in situ reflection high energy electron diffraction, and their magnetic properties were deduced using Moessbauer spectroscopy. The Fe/bcc Ni films were also investigated with x-ray diffraction and fluorescence, and three types of magnetometries. Fe(110)/Ag(111) multilayers were grown, with the Fe layer 3 monolayers thick and the Ag thickness from 4 to 20 ML. For thin Ag spacers, the Fe layers communicated magnetically and gave rise to a T[sup 3/2] dependence. As the Fe layers were separated by thicker Ag layers, they acted more as 2-D ferromagnets and showed a more linear dependence. Another series of films was grown to analyze the B-value of surface spin waves when this Fe surface was separated from another Fe layer. The B-value of the spinwaves exhibited apparent oscillations at separation distances of 5-6 ML. The typical doubling in B-value was seen at the surface. A series of Fe(100)/Ag(100) multilayers were grown on rock salt substrates. Demonstrating a large quadrupole splitting and three different Fe sites, it was postulated that the three sites corresponded to a bulk-like site, a Fe/Ag interface, and a Ag/Fe interface. An [sup 57]Fe probe layer was placed in each of these sites in three different films. The different sites were approximately resolved. Two series of Fe(110)/bcc Ni(110) and Fe(100)/bcc Ni(100) multilayers were grown. RHEED inferred that the Ni grew in a metastable phase of bcc Ni in both orientations. SQUID showed that the (110) type had an order-of-magnitude lower coercivity than the (100). Magnetometry implied that bcc Ni overlayers on Fe with thicknesses of 8 ML and greater are ferromagnetic at room temperature.

• Research Organization: Johns Hopkins Univ., Baltimore, MD (United States)
• OSTI ID: 7236545
• Resource Relation: Other Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
IRON
MAGNETIC PROPERTIES
MOLECULAR BEAM EPITAXY
NICKEL
SILVER
BCC LATTICES
LAYERS
STRUCTURAL CHEMICAL ANALYSIS
THIN FILMS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CUBIC LATTICES
ELEMENTS
EPITAXY
FILMS
METALS
PHYSICAL PROPERTIES
TRANSITION ELEMENTS
360104* - Metals & Alloys- Physical Properties
360101 - Metals & Alloys- Preparation & Fabrication