Title :
Structure and magnetic switching of thin-film a-HITPERM/SiO2 soft magnetic multilayers
Author :
Okumura, H. ; Um, C.-Y. ; Chu, S.Y. ; McHenry, M.E. ; Laughlin, D.E. ; Kos, A.B.
Author_Institution :
Dept. of Mater. Sci. & Eng., Carnegie Mellon Univ., Pittsburgh, PA, USA
fDate :
7/1/2004 12:00:00 AM
Abstract :
Laminated (Fe0.7Co0.3)88Zr7B4Cu1 amorphous HITPERM/SiO2 multilayer thin films have been studied by room-temperature (RT) pulsed inductive microwave magnetometry (PIMM) in single, bilayer, and trilayer films. Switching has been measured in a multilayer film with six (50 nm) HITPERM layers, separated by five (2 nm) SiO2 layers. Films were investigated by conventional transmission electron microscopy (TEM), high-resolution TEM (HREM), and superconducting quantum interference device (SQUID) magnetometry. HREM and TEM show BCC FeCo nanocrystals to nucleate on top of SiO2 layers. Plan view TEM on the top layer reveals FCC nanocrystals that align in chains with spacing of ∼50-100 nm. SQUID magnetometry shows reversal to begin by rotation in a single layer for H<14.4 kA/m (180 Oe) followed by nearly simultaneous reversal of several layers. A final switching event is thermally activated, requiring fields in excess of 8 kA/m (100 Oe) to switch at 2 K, but switching at the same field as other layers for elevated temperatures (RT).
Keywords :
SQUID magnetometers; amorphous magnetic materials; boron alloys; cobalt alloys; copper alloys; crystal structure; iron alloys; magnetic multilayers; magnetic switching; magnetic thin films; soft magnetic materials; transmission electron microscopy; zirconium alloys; (FeCo)88Zr7B4Cu1; 2 K; 2 nm; 50 nm; BCC FeCo nanocrystals; FCC nanocrystals; HITPERM layers; SQUID magnetometry; SiO2; SiO2 multilayer thin films; a-HITPERM; amorphous HITPERM; high-resolution TEM; laminated thin films; magnetic switching; magnetization reversal; pulsed inductive microwave magnetometry; room temperature; soft magnet; soft magnetic multilayers; superconducting quantum interference device; thermally activated switching; transmission electron microscopy; Amorphous magnetic materials; Magnetic films; Magnetic multilayers; Magnetic separation; Magnetic switching; Nanocrystals; SQUIDs; Superconducting films; Superconducting magnets; Switches; Multilayers; PIMM; soft magnet; thermally activated switching;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2004.832109
