Low temperature measurements of the hard magnetic materials.

Hard magnetic materials can be used at low temperatures down to the spin reorientation temperature, Tsr, (eg. around 135 K for Nd-Fe-B). In order to extend the lower limit of usage it is desired to decrease the value of Tsr. This paper reports the influence of different additions and substitutions (Mo, Mo-Cu, Ce) on the hard magnetic properties and Tsr of Nd-Fe-B based films prepared by vacuum deposition. The influence of embedding mode (by alloying or stratification) of additions (i.e. MoCu) in the Nd-Fe-B thin film volume on hard magnetic properties Tsr was also studied. The Nd-Fe-B films with MoCu additions, embedded by stratification, present an increase of the coercive field up to 23.9 kOe and a decrease of Tsr down to 56 K, while Nd-Fe-B films with Ce substitution present a slight deterioration of the magnetic properties and a decrease of Tsr down to 97 K.

硬磁材料可在低至自旋重取向温度（spin reorientation temperature, Tsr）的环境下使用，例如钕铁硼（Nd-Fe-B）的Tsr约为135 K。为拓宽其使用温度下限，亟需降低自旋重取向温度Tsr的数值。本文研究了不同掺杂与取代元素（钼（Mo）、钼铜复合掺杂（Mo-Cu）、铈（Ce））对真空沉积制备的钕铁硼基薄膜的硬磁性能与Tsr的影响。此外，本文还探究了掺杂元素（即MoCu）在钕铁硼薄膜体相中的嵌入方式（合金化掺杂或分层掺杂）对硬磁性能与Tsr的影响。采用分层掺杂方式引入MoCu的钕铁硼薄膜，其矫顽场可提升至23.9 kOe，同时Tsr可降至56 K；而采用Ce取代的钕铁硼薄膜则出现磁性能小幅劣化，但其Tsr可降至97 K。