In this work, computer modeling of the surface phase transition in semi-infinite antiferromagnetic systems under the influence of external magnetic field is carried out. Cases of different values for the surface exchange integral and exchange integral for interaction between surface spins and the first subsurface layer are considered. For the surface phase transition, as for the bulk transition, the Néel temperature decreases with increasing magnetic-field intensity according to the quadratic law. The rate of decrease in the transition temperature is determined by the ratio of exchange integrals on the surface and in the bulk. For each ratio of the exchange integrals, there is a magnetic-field intensity limit above which the surface of the system does not transit into the antiferromagnetic phase. The limiting value of the magnetic field for the surface transition is no lower than the same value for the bulk. There is an interval of the magnetic-field intensity in which the antiferromagnetic ordering of spins is possible only in a thin surface layer. A tricritical point on the system phase diagram is present at the same value of the ratio of the exchange integrals for all magnetic-field-intensity values. The tricritical temperature also decreases in accordance with quadratic law with increasing magnetic-field intensity.

在这项工作中，在外部磁场的影响下，对半无限反铁磁系统中的表面相变进行了计算机建模。考虑表面交换积分和用于表面自旋与第一地下层之间相互作用的交换积分具有不同值的情况。对于表面相变，对于本体相变，奈尔温度根据二次定律随着磁场强度的增加而降低。转变温度的降低速率由表面和本体中交换积分的比例决定。对于交换积分的每个比率，都有一个磁场强度极限，在该极限之上，系统的表面不会过渡到反铁磁相。用于表面转变的磁场的极限值不低于本体的极限值。磁场强度存在一个间隔，其中自旋的反铁磁排序仅在薄表面层中才可能。对于所有磁场强度值，系统相图上的三临界点都存在交换积分比的相同值。随着磁场强度的增加，三临界温度也根据二次定律下降。对于所有磁场强度值，系统相图上的三临界点都存在交换积分比的相同值。随着磁场强度的增加，三临界温度也根据二次定律下降。对于所有磁场强度值，系统相图上的三临界点都存在交换积分比的相同值。随着磁场强度的增加，三临界温度也根据二次定律下降。