【摘要】 采用能量极小原理的微磁学及MonteCarlo方法对铁磁 反铁磁混合磁性薄膜的磁特性进行了模拟计算 ,研究了基态下系统的磁滞回线、自旋组态及铁磁交换作用常数JAA、单轴各向异性常数K、偶极相互作用常数D和铁磁性原子掺杂量X对矫顽力Hc 的影响 .同时还模拟计算了矫顽力Hc 的温度特性 .模拟结果表明 ,在混合磁性薄膜中磁滞回线存在明显的阶梯效应 ,利用简单的Ising模型揭示这种阶梯效应主要起源于包含不同反铁磁原子的掺杂量的不同尺寸的原子团对外加磁场所产生不同响应 ;在基态下当 0 5≤X≤ 1 0时矫顽力Hc 随K ,JAA 的增大而增大 ,但随D增大而减小 ;Hc 随X的变化存在极大值 .这些结果很好地解释了具有反铁磁耦合的颗粒膜的实验事实 .不同X下矫顽力随温度的变化规律可以用Tα 律很好地描述 ,但α值随X却有复杂的变化更多还原

【Abstract】 The magnetic properties of ferromagnetically and antiferromagnetically mixed films are simulated by micromagnetism method based on the principle of energy minimum and Monte Carlo technology. The hysteresis loops, spin configurations, and the influences of exchange constant J AA , uniaxial anisotropy constant K , dipolar interaction constant D and diluted ratio of ferromagnetic atom X on the coercivity H c at the ground states are studied systematically for the systems studied. At the same time, the temperature dependence of the coercivity is calculated. The simulated results indicate that: (1) a step like hysteresis is evidently observed in the mixed magnetic films, and the result calculated by a simple Ising model reveals that the step like effect can be attributed to the different response of the clusters with different size and different diluted ratio of antiferromagnetic atom on the external field; (2) at the ground states, as 0 5≤ X ≤1 0, the value of H c increases with increasing values of K, J AA , but decreases with increasing value of D ; (3) a peak exists in the H c X curves. These simulated results explain the experimental facts about the granular films with antiferromagnetic coupling. The T dependence of the value of H c for the films with different magnitude of X can be well described by the law of T α . But the value of α has a complex variation with the change of X .更多还原