Instituto de Ciencia de Materiales de Aragón, Departamento de Física de la Materia Condensada, CSIC-Universidad de Zaragoza, Zaragoza, Spain.
J Phys Condens Matter. 2013 May 15;25(19):195601. doi: 10.1088/0953-8984/25/19/195601. Epub 2013 Apr 19.
The magnetoelectric properties of the TbMn(1-x)Sc(x)O3 series have been studied at low temperatures by means of heat capacity, magnetic measurements and impedance spectroscopy. TbMnO3 exhibits as expected three transitions upon lowering the temperature corresponding to the magnetic ordering of the two sublattices (Mn and Tb) and the ferroelectric transition. Ferroelectricity disappears with Sc dilution for x > 0.1 because the non-collinear magnetic arrangement is destroyed. The dilution of Mn with a non-magnetic ion is also detrimental to the magnetic ordering of both Mn and Tb sublattices. The system evolves to a magnetic glassy state for the intermediate compositions. Formal TbScO3 shows Sc-deficiency and long range magnetic ordering of Tb(3+) moments in the ab-plane brought by the direct interaction between Tb(3+) ions. This ordering is different from the one found in TbMnO3 due to the lack of magnetic coupling between Tb- and Mn-sublattices. A small substitution of Sc by Mn in TbScO3 destroys the Tb ordering giving rise to a magnetic glass behaviour. This effect is ascribed to the partial polarization of Tb sublattice by the paramagnetic Mn which competes with the direct Tb-Tb exchange.
通过比热、磁测量和阻抗谱研究了 TbMn(1-x)Sc(x)O3 系列在低温下的磁电性质。TbMnO3 在降低温度时表现出预期的三个转变，对应于两个亚晶格（Mn 和 Tb）的磁有序和铁电转变。随着 Sc 稀释（x > 0.1），铁电性消失，因为非共线磁排列被破坏。用非磁性离子稀释 Mn 也不利于 Mn 和 Tb 亚晶格的磁有序。对于中间组成，系统演变为磁性玻璃态。形式上的 TbScO3 表现出 Sc 缺乏和 ab 平面上 Tb(3+) 磁矩的长程有序，这是由 Tb(3+) 离子之间的直接相互作用带来的。这种有序与在 TbMnO3 中发现的不同，因为 Tb-和 Mn-亚晶格之间没有磁耦合。在 TbScO3 中用 Mn 少量取代 Sc 会破坏 Tb 有序，导致磁性玻璃行为。这种效应归因于顺磁 Mn 对 Tb 亚晶格的部分极化，它与直接的 Tb-Tb 交换竞争。
