Ni $_{1-x}$ Rh $_x$块体合金在临界浓度$x_c \sim$ 0.37处表现出铁磁到顺磁的量子相变(QPT)。通过控制Ni和Rh原子间的短程相互作用,在铁磁性层下方出现了一个自旋玻璃相。我们采用化学回流法合成了两种不同浓度和两种不同反应时间的纳米合金。从直流磁化强度测量,铁磁性和自旋玻璃相的存在,在这些纳米合金被证实。在一定温度下,ZFC和FC曲线均呈现台阶状特征,表明存在自旋玻璃相。
英文摘要:
Ni$_{1-x}$Rh$_x$ bulk alloys exhibit a ferromagnetic to paramagnetic quantum phase transition (QPT) at the critical concentration $x_c \sim$ 0.37. A spin glass phase arises below the Ferromagnetism by controlling the short range interaction between Ni and Rh atoms. we have synthesized nanoalloys of two different concentrations with two different reaction times by chemical reflux method. From the dc magnetization measurements, existence of ferromagnetism and spin glass phase in these nanoalloys is confirmed. A step like feature in both ZFC and FC curve at certain temperature indicates the existence of the spin glass phase.
Local optical control of ferromagnetism and chemical potential in a topological insulator
许多涉及拓扑绝缘体(TI)的实验需要对时间反演对称性和化学势进行空间控制。我们展示了可重构的微米尺度的光学控制的磁化强度(打破时间反转对称性)和化学势的铁磁薄膜的Cr-(Bi,Sb)$_2$ Te $_3$生长在SrTiO $_3$。通过光学调制薄膜的磁化率,我们在它们的回复磁化中写入和擦除任意图案,然后用克尔显微镜成像。此外,通过光学操纵的空间电荷层在下面的SrTiO $_3$衬底,我们控制的局部化学势的薄膜。这种光学选通效应使我们能够在薄膜中写入和擦除pn结,我们用光电流显微镜研究。这两种效应都是持久的,并且可以在几微米尺度上独立地形成图案和成像。动态光学控制的磁化强度和化学势的TI可能是有用的努力,以了解和控制的边缘状态预测在磁畴壁的量子异常霍尔绝缘体。
Enhanced room temperature ferromagnetism in nanostructured MoS2 flakes by hydrogen post-treatment: Combined experimental and first-principles-based studies