Magnetic properties and growth texture of high-coercive Nd-Fe-B thin films

被引:47
作者
Parhofer, S
Kuhrt, C
Wecker, J
Gieres, G
Schultz, L
机构
[1] Siemens AG, Corp Res & Dev, D-91050 Erlangen, Germany
[2] IFW, Inst Solid State & Mat Res, D-01171 Dresden, Germany
关键词
D O I
10.1063/1.366635
中图分类号
O59 [应用物理学];
学科分类号
摘要
We have investigated the growth texture and magnetic properties of sputtered Nd-Fe-B thin films with thicknesses from 5 to 350 nm. Films deposited directly onto a quartz substrate grow with a pronounced c-axis texture perpendicular to the film plane and have a coercivity of about 160 kA/m. If the films thickness is reduced below 150 nm, a significant part of the Nd is oxidized by substrate oxygen and the coercivity decreases to values below 20 kA/m. The deposition of a 80 nm Cr buffer layer between substrate and Nd-Fe-B film prevents oxidation of the film and decreases the growth texture of the films. This enables us to fabricate Nd-Fe-B films as thin as 20 nm with good hard magnetic properties [H-cj = 800 kA/m, J(r) = 1.1 T, and a maximum energy product (BH)(max) = 190 kJ/m(3) perpendicular to film plane]. An inverse relationship between growth texture and coercivity is found which can be understood in terms of domain wall motion. The deposition of a Cr buffer leads to an island type of growth and a high surface roughness, while films without Cr buffer are very smooth. By depositing a protective Cr layer on top of the film, the corrosion resistance can be enhanced. (C) 1998 American Institute of Physics.
引用
收藏
页码:2735 / 2741
页数:7
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