Condensed Matter Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102, India.
J Phys Condens Matter. 2013 Oct 30;25(43):436001. doi: 10.1088/0953-8984/25/43/436001. Epub 2013 Oct 4.
We present magnetization and resistance measurements carried out on pristine and Ca-doped Gd(1-x)Ca(x)BaCo2O5.5 (x = 0.02) samples using the cooling and heating in unequal field (CHUF) protocol. The measurements reveal that the high temperature ferromagnetic phase is kinetically arrested at low temperature when the sample is cooled in a magnetic field. The volume fraction of this arrested phase increases upon Ca substitution and also by increasing the field in which the sample is cooled. Since the ferromagnetic phase is less resistive when compared to the low temperature antiferromagnetic phase, a tunable resistance is achieved in the sample by cooling in different magnetic fields. By cooling in magnetic fields of 9 T a reduction in resistivity by an order of magnitude is achieved. These results are consistent with the coexistence of the low temperature equilibrium antiferromagnetic phase with kinetically arrested high temperature ferromagnetic phase in the system.
我们呈现了在原始和 Ca 掺杂的 Gd(1-x)Ca(x)BaCo2O5.5（x = 0.02）样品上进行的磁化和电阻测量，使用冷却和加热非平衡场（CHUF）协议。测量结果表明，当样品在磁场中冷却时，高温铁磁相在低温下被动力学捕获。这种被捕获的相的分数随着 Ca 取代的增加以及冷却样品的场的增加而增加。由于铁磁相的电阻比低温反铁磁相的电阻小，因此通过在不同磁场中冷却可以在样品中实现可调电阻。通过在 9 T 的磁场中冷却，可以实现电阻率降低一个数量级。这些结果与系统中低温平衡反铁磁相与动力学捕获的高温铁磁相共存的情况一致。
