Granzow T, Woike Th, Wöhlecke M, Imlau M, Kleemann W
Institut für Mineralogie, Universität zu Köln, Zülpicherstrasse 49b, D-50674 Cologne, Germany.
Phys Rev Lett. 2004 Feb 13;92(6):065701. doi: 10.1103/PhysRevLett.92.065701. Epub 2004 Feb 10.
Pyroelectric measurements of polarization have been used to determine the temperature dependence of the polarization in strontium barium niobate, SBN:Ce, close to its phase transition temperature T(c) approximately 317 K. A gradual increase of the critical exponent from beta approximately 0.13 to beta approximately 0.30 is observed when decreasing the initial polarization from 100% to 0.8% of the saturation value. A change from three-dimensional random-field Ising to pure Ising model behavior is conjectured and explained by a gradual compensation of quenched random electric fields by those emerging from charged fractal nanodomain walls.
利用热释电极化测量法来确定铌酸锶钡（SBN:Ce）中极化随温度的变化关系，该温度接近其相变温度T(c)，约为317K。当将初始极化从饱和值的100%降低至0.8%时，观察到临界指数从β≈0.13逐渐增加至β≈0.30。推测从三维随机场伊辛模型行为转变为纯伊辛模型行为，并通过带电分形纳米畴壁产生的电场对淬火随机电场的逐渐补偿来解释。
