Superparamagnetic relaxation of Fe deposited on MgO(001)

Journal Article · Wed Nov 01 04:00:00 EST 1995 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.52.12779· OSTI ID:122314

Park, Y; Adenwalla, S; Felcher, G P; Bader, S D ^[1]

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1. Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

Superparamagnetic behavior is investigated for Fe grown at 700 K onto MgO(001) to a thickness equivalent to that of a ten monolayer film. Two such Fe deposits separated by a 200-A deposit of MgO exhibit a ferromagnetic response with no hysteresis at either 300 or 150 K, but with identical reduced magnetization curves {ital M}({ital H}/{ital T}) which confirms the existence of superparamagnetism. {ital M}({ital H}) data at 300 K were fitted to a Langevin function to yield an average particle size of 100 A diameter. {ital M}({ital T}) for field-cooled and zero-field-cooled samples shows behavior characteristic of superparamagnetic particles with a distribution in particle size. Time-dependent remanent magnetization data measured over a 20 h period at various temperatures show nonexponential decay attributed to the distribution in particle size and interactions among the particles.

• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 122314
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 17 Vol. 52; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
IRON
MAGNESIUM OXIDES
MAGNETIZATION
SUPERPARAMAGNETISM
TEMPERATURE DEPENDENCE
TIME DEPENDENCE