Anisotropic magnetic behavior in Dy/Y films and superlattices

Journal Article · Sat Jun 01 04:00:00 EDT 1991 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.43.13320· OSTI ID:5625191

Tsui, F; Flynn, C P; Salamon, M B ^[1]; Erwin, R W; Borchers, J A; Rhyne, J J ^[2]

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1. Department of Physics and Materials Research Laboratory, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801 (USA)
2. National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (USA)

By neutron diffraction we show that superlattices of Dy and Y grown by molecular-beam epitaxy along the hcp {ital b} axis exhibit little magnetic coupling between successive Dy layers, even for Y spacers as thin as 9 atomic planes (26 A). Previous studies of Dy/Y superlattices grown along the hcp {ital c} axis established that long-range three-dimensional helimagnetic ordering takes place even through Y spacer layers as thick as 120 A. This highly anisotropic coupling behavior is shown to have its origin in nearly-two-dimensional nesting features of the Y and Dy Fermi surfaces. Nesting along the {ital c} axis gives rise to sharp peaks along {bold c} in the wave-vector-dependent magnetic susceptibility, and causes the exchange coupling to exhibit long-range oscillations in real space. The lack of nesting features along the {ital b} axis leaves a rapid exponential decay of the exchange interaction with spin separation. From magnetic measurements by superconducting-quantum-interference-device magnetometry on {ital b}-axis superlattices and films, we deduce that the first-order ferromagnetic transition of Dy is suppressed, and that the critical field required to produce the ferromagnetic alignment is much higher than the {ital c}-axis counterpart. This difference arises from anisotropy of the energy balance of the system. The magnetic coherence in {ital b}-axis superlattices and films is anisotropic and exhibits an unusual temperature dependence.

• OSTI ID: 5625191
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 43:16; ISSN 0163-1829; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
ANISOTROPY
COHERENT SCATTERING
DIFFRACTION
DYSPROSIUM
ELECTRONIC EQUIPMENT
ELEMENTS
ENERGY LEVELS
EPITAXY
EQUIPMENT
EXCHANGE INTERACTIONS
FERMI LEVEL
FILMS
FLUXMETERS
INTERACTIONS
MAGNETIC PROPERTIES
MAGNETIC SUSCEPTIBILITY
MEASURING INSTRUMENTS
METALS
MICROWAVE EQUIPMENT
MOLECULAR BEAM EPITAXY
NEUTRON DIFFRACTION
PHYSICAL PROPERTIES
RARE EARTHS
SCATTERING
SQUID DEVICES
SUPERCONDUCTING DEVICES
SUPERLATTICES
TRANSITION ELEMENTS
YTTRIUM