| Autor: |
Chen, Christina H., Walmer, Marlin S., Walmer, Michael H., Liu, Jinfang, Liu, Sam, Kuh, G. E. |
| Předmět: |
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| Zdroj: |
Journal of Applied Physics; 5/1/2000, Vol. 87 Issue 9, p6719, 3p, 3 Charts, 2 Graphs |
| Abstrakt: |
A new series of Sm(Co[sub w]Fe[sub v]Cu[sub x]Zr[sub y])[sub z] alloys has been developed to produce magnets with high intrinsic coercivity [sub i]H[sub c] at high temperatures for use up to 550 °C. The maximum use temperature is defined as T[sub M], which is the maximum temperature at which the extrinsic demagnetization curve is a straight line. An important feature of the alloys with high T[sub M] is a lower temperature coefficient of [sub i]H[sub c], β. These magnets have a higher resistance to demagnetization from increasing thermal agitation which occurs with increasing temperature. A study on magnetic pinning field H[sub p], which will be explained in the text, vs T[sub M] was conducted by measuring the initial magnetization curves of the magnets at 25 and 300 °C. The study shows that as T[sub M] increases, H[sub p] increase at high temperatures. At 25 °C, all magnets with T[sub M] from 250 to 550 °C have H[sub p] higher than 24 kOe, which is too high to be determined using a hysteresigraph. At 300 °C, the magnet with T[sub M]=250 °C has H[sub p]=7.0 kOe, and the magnet with T[sub M]=550 °C has H[sub p]=15.1 kOe. Higher pinning field at high temperatures (>=300 °C) provides a greater resistance to thermal demagnetization, which leads to better performance at high temperatures. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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