ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
We report studies of magnetic properties in CoX A(ring)/Au60 A(ring) multilayers (X=5,6,7,8,12,20 A(ring)), which were prepared by sputtering on Si(111) substrates, with emphasis on the magnetization reversal. Magnetization reversal was investigated by measurements of initial magnetization curves, minor loops, coercivity as a function of the maximum field of minor loops, temperature dependence of magnetic properties using Kronmüller's model, time decay of Kerr rotation angle aitch-thetaK, and the field-sweep speed dependence of coercivity Hc(dHa/dt) at room and/or low temperature. It is found that (1) the thermal activation volumes determined by Hc(dHa/dt) increase from ∼2.0×10−17 to ∼9.9×10−17 cm3 as X varies from 5 to 20 A(ring), which corresponds to a cylindrical activation volume with ∼800 A(ring) diameter. (2) A Kronmüller analysis together with the initial magnetization curves, etc., for a Co5 A(ring)/Au60 A(ring) sample at room and low temperature indicates that wall pinning with small pinning sites is the major coercivity mechanism. The interaction between grains was studied with the so-called ΔM method: samples with thin Co layers (X=5,6,7 A(ring)), which show perpendicular anistropy, exhibit negative ΔM or dipolar interactions, while samples with a thick Co layer (e.g., X=20 A(ring)), which show in-plane anisotropy, exhibit positive ΔM or ferromagnetic exchange interactions. © 1996 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.361672
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