Observation of a temperature dependent asymmetry in the domain structure of a Pd doped FeRh epilayer
C. J. Kinane, M. Loving, M. A. de Vries, R. Fan, T. R. Charlton, J. S. Claydon, D. A. Arena, F. Maccherozzi, S. S. Dhesi, D. Heiman, C. H. Marrows, L. H. Lewis, Sean Langridge
Using X-ray photoelectron emission microscopy we have observed the coexistence of ferromagnetic and antiferromagnetic phases in a (3 at.%)Pd-doped FeRh epilayer. By quantitatively analyzing the resultant images we observe that as the epilayer transforms there is a change in magnetic domain symmetry from predominantly twofold at lower temperatures through to an equally weighted combination of both four and twofold symmetries at higher temperature. It is postulated that the lowered symmetry Ising-like nematic phase resides at the near-surface of the epilayer. This behavior is different to that of undoped FeRh suggesting that the variation in symmetry is driven by the competing structural and electronic interactions in the nanoscale FeRh film coupled with the effect of the chemical doping disorder.
Thermoelectric determination of electronic entropy change in Ni-doped FeRh
利用外加磁场下的低温热容实验，以及高温下的Seebeck效应和Hall系数测量，对Ni掺杂FeRh块状多晶中载流子的净熵变进行了实验研究.从热容数据中提取出电子熵变\(ΔS_{el}\approx8.9\) J\ kg \(^{-1}\) K \(^{-1}\)的值，而从塞贝克系数中获得高达4 J\ kg \(^{-1}\) K \(^{-1}\)的值。此外，塞贝克系数的分析允许跟踪的电子熵变化与所施加的磁场的演变。电子熵随外加磁场的增加而增加，在6 T时可达10%.
