Upadhyay Sanjay K, Sampathkumaran E V
Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India.
J Phys Condens Matter. 2019 Oct 2;31(39):39LT01. doi: 10.1088/1361-648X/ab2d0f. Epub 2019 Jun 26.
The Haldane spin-chain compound, TbBaNiO, with two antiferromagnetic transitions, one at T = 63 K and the other at T = 25 K, has been recently shown to be an exotic multiferroic below T . Here, we report the results of our investigation of Sr doping at the Ba site by magnetization, heat-capacity, magnetodielectric (MDE) and pyrocurrent measurements. An intriguing finding, which we stress, is that the ferroelectricity is lost even for a doping level of ten atomic percent, though magnetic ordering prevails. The doped specimens however retain significant MDE behaviour, but with reduced magnitudes and qualitative changes with respect to the behaviour of the parent compound. This implies that ferroelectric order is also crucial for the anomalously large MDE in the parent compound, in addition to the role of 4f single-ion anisotropy.
具有两个反铁磁转变的霍尔丹自旋链化合物TbBaNiO，一个转变温度为T = 63K，另一个为T = 25K，最近已被证明在T以下是一种奇异的多铁性材料。在此，我们报告通过磁化、热容量、磁电（MDE）和热电流测量对Ba位进行Sr掺杂的研究结果。我们强调的一个有趣发现是，即使掺杂水平为10原子百分比，铁电性也会丧失，尽管磁有序仍然存在。然而，掺杂样品保留了显著的MDE行为，但相对于母体化合物的行为，其幅度减小且有定性变化。这意味着除了4f单离子各向异性的作用外，铁电有序对于母体化合物中异常大的MDE也至关重要。
