Kapustianyk V, Eliyashevskyy Yu, Czapla Z, Rudyk V, Serkiz R, Ostapenko N, Hirnyk I, Dayen J-F, Bobnar M, Gumeniuk R, Kundys B
Scientific-Technical and Educational Center of Low-Temperature Studies, Ivan Franko National University of Lviv, Dragomanova str. 50, 79005, Lviv, Ukraine.
Department of Physics, Ivan Franko National University of Lviv, Dragomanova str. 50, 79005, Lviv, Ukraine.
Sci Rep. 2017 Oct 26;7(1):14109. doi: 10.1038/s41598-017-14388-8.
Hybrid organometallic systems offer a wide range of functionalities, including magnetoelectric (ME) interactions. However, the ability to design on-demand ME coupling remains challenging despite a variety of host-guest configurations and ME phases coexistence possibilities. Here, we report the effect of metal-ion substitution on the magnetic and electric properties in the paramagnetic ferroelectric NH(CH)Al Cr (SO) × 6HO. Doing so we are able to induce and even tune a sign of the ME interactions, in the paramagnetic ferroelectric (FE) state. Both studied samples with x = 0.065 and x = 0.2 become paramagnetic, contrary to the initial diamagnetic compound. Due to the isomorphous substitution with Cr the ferroelectric phase transition temperature (T ) increases nonlinearly, with the shift being larger for the 6.5% of Cr. A magnetic field applied along the polar c axis increases ferroelectricity for the x = 0.065 sample and shifts T to higher values, while inverse effects are observed for x = 0.2. The ME coupling coefficient α = 1.7 ns/m found for a crystal with Cr content of x = 0.2 is among the highest reported up to now. The observed sign change of α with a small change in Cr content paves the way for ME coupling engineering.
混合有机金属体系具有广泛的功能，包括磁电（ME）相互作用。然而，尽管存在多种主客体构型以及ME相共存的可能性，但按需设计ME耦合的能力仍然具有挑战性。在此，我们报道了金属离子取代对顺磁性铁电体NH(CH)Al Cr (SO) × 6HO的磁性和电学性质的影响。通过这样做，我们能够在顺磁性铁电（FE）状态下诱导甚至调节ME相互作用的符号。与初始的抗磁性化合物相反，研究的x = 0.065和x = 0.2的样品都变成了顺磁性。由于用Cr进行同构取代，铁电相变温度（T ）非线性增加，Cr含量为6.5%时的位移更大。沿极性c轴施加的磁场会增加x = 0.065样品的铁电性，并将T 移至更高值，而对于x = 0.2则观察到相反的效果。对于Cr含量为x = 0.2的晶体，发现的ME耦合系数α = 1.7 ns/m是迄今为止报道的最高值之一。观察到的α随Cr含量的微小变化而发生的符号变化为ME耦合工程铺平了道路。
