c/a ratio effects on the magnetic properties of the Mn₂NiB Heusler alloy are investigated by using effective field theory developed by Kaneyoshi. It is found that the Curie temperature and coercive fields of the Mn₂NiB are obtained as Tc^IT > Tc^C > Tc^NT = 0.92 and Hc^IT > Hc^C > Hc^NT = 0.00 for c/a < 1 (inverse tetragonal), c/a = 1 (cubic), and c/a > 1 (normal tetragonal), respectively. These magnetic differences show that the c/a ratio causes a perpendicular magnetic anisotropy (PMA). Therefore, we suggest that PMA strongly depends on the c/a ratio, atomic distance, and exchange interactions between two atoms (Mn–Ni and Mn–B) on the ca surfaces of the Mn₂NiB.

c / a比对通过使用Kaneyoshi开发的有效场论研究了Mn ₂ NiB Heusler合金的磁性能。发现 对于c / a  <1（反四边形），Mn ₂ NiB的居里温度和矫顽场为Tc ^IT > Tc ^C > Tc ^NT  = 0.92和Hc ^IT > Hc ^C > Hc ^NT = 0.00 ，c / a  = 1（立方），c / a  > 1（正四边形）。这些磁差表明c / a比率导致垂直磁各向异性（PMA）。因此，我们认为PMA在很大程度上取决于c / a比，原子距离以及Mn ₂ NiB的ca表面上两个原子（Mn-Ni和Mn-B）之间的交换相互作用。