Dresden 2006 – scientific programme

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MA: Magnetismus

MA 14: Magnetic Thin Films II

MA 14.10: Talk

Tuesday, March 28, 2006, 12:30–12:45, HSZ 03

Effect of composition on Nd-Fe-B hard magnetic thin films — •Ah-Ram Kwon, Sebastian Fähler, Volker Neu, and Ludwig Schultz — IFW Dresden, , Institute for Metallic Materials, P.O. Box 270116, D-01171 Dresden, Germany

While for bulk Nd₂Fe ₁₄B the influence of composition on microstructure, phase formation and texture is understand quite well, only little work exists on thin films. The Nd₂Fe ₁₄B phase has only a very narrow existing range, thus in bulk materials a derivation from stoichometry (2:14:1) results in the formation of additional phases. Nd-Fe-B hard magnetic thin films were deposited on a combinded Cr/Ta buffer layer on heated MgO(100)substrates by pulsed laser deposition. On this buffer system Nd₂Fe ₁₄B grows epitaxial in one single orientation. This allows a detailed examination of the intrinsic properties and results in an almost perfect magnetic texture. The effect of composition on phase formation, morphology and magnetic properties was investigated. Optimum phase formation is obtained at a Nd/Fe ratio around 0.3. For this Nd content an excellent magnetic texture and a coercivity up to 1 T can be obtained; however, films have a granular microstructure with high roughness. Also a certain B surplus is of benefit; though with a too high B or Nd surplus phase formation is more difficult.