Research Institute of Physics and the Facultyof Physics, Southern Federal University, Rostov on Don, Russia.
IEEE Trans Ultrason Ferroelectr Freq Control. 2012 Sep;59(9):1872-8. doi: 10.1109/TUFFC.2012.2399.
In the present study, we diluted either A- or B- sublattice of perovskite multiferroic PbFe(0.5)Nb(0.5)O(3) (PFN) and studied the changes of the magnetic and ferroelectric phase transition temperatures and dielectric properties caused by such dilution. Dielectric studies of PFN single crystals show that, in contrast to the commonly adopted view, the ferroelectric phase transition in PFN is non-diffused and the relaxor-like behavior usually observed in ceramic samples has an extrinsic nature. A-site substitutions (Ba, Ca) lead to the smearing of the permittivity-temperature maximum, lowering its maximum temperature, T(m) and inducing relaxor behavior. B-site diluting of PFN by Ti increases T(m) and only slightly affects the permittivity maximum diffuseness. Both A-site and B-site substitutions in PFN lead to lowering of its Neel temperature, T(N). However, above a certain compositional threshold, fast lowering of T(N) stops and a new magnetic state with comparatively high (~50K) transition temperature becomes stable in a rather wide compositional range.
在本研究中，我们对钙钛矿多铁性 PbFe(0.5)Nb(0.5)O(3) (PFN)的 A 位或 B 位进行了稀释，并研究了这种稀释引起的磁相和铁电相转变温度以及介电性能的变化。PFN 单晶的介电研究表明，与通常采用的观点相反，PFN 中的铁电相转变是非扩散的，而在陶瓷样品中通常观察到的类弛豫行为具有外在性质。A 位取代（Ba、Ca）导致介电常数-温度最大值的弥散，降低其最大值温度 T(m)并诱导弛豫行为。通过 Ti 对 PFN 的 B 位稀释会提高 T(m)，并仅略微影响介电常数最大值的弥散。PFN 的 A 位和 B 位取代都会降低其奈尔温度 T(N)。然而，在一定的组成阈值之上，T(N)的快速降低停止，并且在相当宽的组成范围内，一种新的具有相对较高(~50K)转变温度的磁态变得稳定。
