Evidence of partial gap opening and Ce-site dilution effects in a heavy fermion compound CeNiGe₂

Abstract

We report the results of magnetization, non-linear dc susceptibility, electrical transport, and heat capacity measurements on Y-substituted heavy fermion CeNiGe 2 . Investigations are carried out on the compounds CeNiGe 2 , Ce 0.9 Y 0.1 NiGe 2 , Ce 0.8 Y 0.2 NiGe 2 and Ce 0.6 Y 0.4 NiGe 2 . It is observed that with the increase in Y-concentration, the magnetic ordering temperature decreases.For CeNiGe 2 , below ordering temperature Arrott plots suggest the presence of spin density wave (SDW). Third and fifth order dc susceptibility indicates magnetic instability which possibly leads to partial gap opening resulting in the observation of SDW. These observations are further investigated through resistivity and heat capacity measurements which also point toward partial gap opening in CeNiGe 2 . Interestingly, with the increase in Y-substitution, it is noted that the gap opening is suppressed and also shifted towards lower temperature. Moreover, our investigations reveal absence of non-Fermi liquid behavior or zero field quantum critical point even after 40% dilution of Ce-site.

Melting of spin ice state and development of fifth order susceptibility with magnetic field in pyrochlore Tb2Sn2O7

“…In general terms, magnetization in the direction of applied magnetic field can be expanded as [33][34][35]:…”

“…where χ 1 is the linear term associated with dipolar moments, χ 3 and χ 5 are the non-linear terms associated with higher-order moments. For determination of χ 3 and χ 5 , magnetization data (under field cooled condition) was collected with slow cooling rate of 5 mK s −1 at a constant field, similar to the protocol as mentioned in reference [33,34]. Figure 5(a) shows M/H plotted as a function of H 2 .…”

Evolution of field induced magnetic phase attributed to higher order magnetic moments in TbVO4

“…Generally, magnetization along the direction of magnetic field can be expanded in the form 34 – 38 : where χ 1 is the linear term associated with dipolar moments, χ 3 and χ 5 are the non-linear terms associated with higher-order moments. In order to evaluate the higher order moments ( χ 3 and χ 5 ), magnetization data was collected under the FC condition with slow cooling rate of 5 mK/s at a constant field, similar to the protocols mentioned in the references 35 , 38 . M / H versus H 2 curves at different temperatures are plotted in the Fig.…”

Possibility of a new order parameter driven by multipolar moment and Fermi surface evolution in CeGe

“…In order to investigate the possibility of the presence of higher order magnetization in this complex magnetic state, the non-linear DC susceptibility (as a probe of higher order spin correlations) is studied, using the protocol as given in refs 19 , 20 . Figure 3(c) show the H 2 dependent M / H curves at selected temperature upto 15 K. Below T I , it is noted that M / H decreases linearly with H 2 and at low field (below 1 T), the curves sharply increases with decreasing magnetic field due to the presence of the ferromagnetic component.…”

“…In order to investigate the possibility of the presence of higher order magnetization in this complex magnetic state, the non-linear DC susceptibility (as a probe of higher order spin correlations) is studied, using the protocol as given in Ref [19,20]. Figure 3…”