Open AccessNanostructure and hard magnetic properties of exchange coupled Nd-Fe-B/FeCo multilayer films
Author(s) -
Qi Ao,
Wali Zhang,
Yi Zhang,
Jiansheng Wu
Publication year - 2007
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.56.1135
Subject(s) - materials science , coercivity , remanence , amorphous solid , nanocomposite , annealing (glass) , high resolution transmission electron microscopy , grain size , thin film , sputtering , sputter deposition , film plane , magnetization , magnetic anisotropy , composite material , nanotechnology , condensed matter physics , transmission electron microscopy , crystallography , magnetic field , physics , chemistry , quantum mechanics
The nanocomposite Nd-Fe-B/FeCo mutilayer films have been prepared by rf sputtering. XRD results and HRTEM observation showed that as-deposited films deposited at substrate temperature of 300K were amorphous. The columnar grains of Nd2Fe14B phase with the c-axis perpendicular to the film plane developed after annealing at 923 K for 15 min. Nd2Fe14B grain size was about 10 nm in average and Nd-O particles of about 7 nm were dispersed within the grains and along the grain boundaries. The magnetization of these samples is found to increase with increasing FeCo layer thickness (tFeCo) and the coercivity decreases with increasing tFeCo. The multilayer films of maximum energy product is 200 kJ/m3 for tFeCo=5 nm at room temperature. The enhancement of the remanence and energy product in nanocomposite films is attributed to the exchange coupling between the magnetically hard and soft phases.