Abstract
Magnetic materials are classed as 'soft' if they have a low coercivity (the critical field strength H(c) required to flip the direction of magnetization). Soft magnetic materials are a central component of electromagnetic devices such as step motors, magnetic sensors, transformers and magnetic recording heads. Miniaturization of these devices requires materials that can develop higher saturation flux density, B3, so that the necessary flux densities can be preserved on reducing device dimensions, while simultaneously achieving a low coercivity. Common high-B3 soft magnetic films currently in use are electroplated CoFe-based alloys, electroplated CoNiFe alloys, and sputtered Fe-based nanocrystalline and FeN films. Sputtering is not suitable, however, for fabricating the thick films needed in some applications, for which electrochemical methods are preferred. Here we report the electrochemical preparation of a CoNiFe film with a very high value of B(s) (2.0-2.1 T) and a low coercivity. The favourable properties are achieved by avoiding the need for organic additives in the deposition process, which are typically used to reduce internal stresses. Our films also undergo very small magnetostriction, which is essential to ensure that they are not stressed when an external magnetic field is applied (or conversely, that external stresses do not disrupt the magnetic properties). Our material should find applications in miniaturization of electromechanical devices and in high-density magnetic data storage.
| Original language | English |
|---|---|
| Pages (from-to) | 796-798 |
| Number of pages | 3 |
| Journal | Nature |
| Volume | 392 |
| Issue number | 6678 |
| DOIs | |
| Publication status | Published - 1998 Apr 23 |
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A soft magnetic CoNiFe film with high saturation magnetic flux density and low coercivity. / Osaka, Tetsuya; Takai, Madoka; Hayashi, Katsuyoshi; Ohashi, Keishi; Saito, Mikiko; Yamada, Kazuhiko.
In: Nature, Vol. 392, No. 6678, 23.04.1998, p. 796-798.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - A soft magnetic CoNiFe film with high saturation magnetic flux density and low coercivity
AU - Osaka, Tetsuya
AU - Takai, Madoka
AU - Hayashi, Katsuyoshi
AU - Ohashi, Keishi
AU - Saito, Mikiko
AU - Yamada, Kazuhiko
PY - 1998/4/23
Y1 - 1998/4/23
N2 - Magnetic materials are classed as 'soft' if they have a low coercivity (the critical field strength H(c) required to flip the direction of magnetization). Soft magnetic materials are a central component of electromagnetic devices such as step motors, magnetic sensors, transformers and magnetic recording heads. Miniaturization of these devices requires materials that can develop higher saturation flux density, B3, so that the necessary flux densities can be preserved on reducing device dimensions, while simultaneously achieving a low coercivity. Common high-B3 soft magnetic films currently in use are electroplated CoFe-based alloys, electroplated CoNiFe alloys, and sputtered Fe-based nanocrystalline and FeN films. Sputtering is not suitable, however, for fabricating the thick films needed in some applications, for which electrochemical methods are preferred. Here we report the electrochemical preparation of a CoNiFe film with a very high value of B(s) (2.0-2.1 T) and a low coercivity. The favourable properties are achieved by avoiding the need for organic additives in the deposition process, which are typically used to reduce internal stresses. Our films also undergo very small magnetostriction, which is essential to ensure that they are not stressed when an external magnetic field is applied (or conversely, that external stresses do not disrupt the magnetic properties). Our material should find applications in miniaturization of electromechanical devices and in high-density magnetic data storage.
AB - Magnetic materials are classed as 'soft' if they have a low coercivity (the critical field strength H(c) required to flip the direction of magnetization). Soft magnetic materials are a central component of electromagnetic devices such as step motors, magnetic sensors, transformers and magnetic recording heads. Miniaturization of these devices requires materials that can develop higher saturation flux density, B3, so that the necessary flux densities can be preserved on reducing device dimensions, while simultaneously achieving a low coercivity. Common high-B3 soft magnetic films currently in use are electroplated CoFe-based alloys, electroplated CoNiFe alloys, and sputtered Fe-based nanocrystalline and FeN films. Sputtering is not suitable, however, for fabricating the thick films needed in some applications, for which electrochemical methods are preferred. Here we report the electrochemical preparation of a CoNiFe film with a very high value of B(s) (2.0-2.1 T) and a low coercivity. The favourable properties are achieved by avoiding the need for organic additives in the deposition process, which are typically used to reduce internal stresses. Our films also undergo very small magnetostriction, which is essential to ensure that they are not stressed when an external magnetic field is applied (or conversely, that external stresses do not disrupt the magnetic properties). Our material should find applications in miniaturization of electromechanical devices and in high-density magnetic data storage.
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U2 - 10.1038/33888
DO - 10.1038/33888
M3 - Article
AN - SCOPUS:0032560161
VL - 392
SP - 796
EP - 798
JO - Nature
JF - Nature
SN - 0028-0836
IS - 6678
ER -