Ferrimagnetism and abnormal spin lattice coupling in dilute magnetic ferroelectric (Bi0.46 Na0.46 Ba0.08)TiO3:Co

We have investigated the low-temperature magnetism and spin-lattice coupling in (Bi 0.46 Na 0.46 Ba 0.08)TiO 3:Co in order to understand the magnetoelectric effect in such artificially synthesized dilute magnetic ferroelectrics.It is revealed that the as-prepared (Bi 0.46 Na 0.46 Ba 0.08)TiO 3:Co at Co content of 20%～30% exhibits fascinating ferrimagnetism which is robust against magnetic field,the abnormal spin-lattice coupling characterized by a negative magnetostriction effect;and the suppressed magnetic moment within the temperature range of 30 K～50 K is identified.These magnetic behaviours at low temperatures can be explained by the competition between the ferrimagnetic response and the magnetic moment suppression induced by the abnormal spin-lattice coupling effect.Finally,the ferroelectric and magnetodielectric properties are also discussed.     

二价硅离子高于3s3p态能级间自旋允许跃迁的理论计算

在最弱受约束电子势模型理论中，电子被分成最弱受约束电子和非最弱受约束电子，而假定最弱受约束电子在核和非最弱受约束电子形成的势场中运动，这样许多多电子体系的问题可以简化成最弱受约束电子的单电子问题来解决．最弱受约束电子势模型理论已经被成功地应用于跃迁几率，振子强度和原子能级的计算．应用一组方程计算了Si III的离子自旋允许跃迁的跃迁几率，计算结果与标准值比较是相当令人满意的，误差均在15%以下．而且表明最弱受约束电子势模型理论可以非常简便并准确地应用于计算高激发态间的跃迁几率．