In this work, we investigate the magnetic, heat capacity and electrical transport properties of Ce 0.6 La 0.4 Ge and Ce 0.24 La 0.76 Ge compounds. Our results show that two antiferromagnetic transitions (~ at 4.7 and 2.7 K) exhibited by Ce 0.6 La 0.4 Ge are suppressed below 1.8 K for Ce 0.24 La 0.76 Ge. Interestingly, for Ce 0.24 La 0.76 Ge, susceptibility, heat capacity and electrical resistivity vary with temperature as: T 0.75 , T 0.5 and T 1.6 respectively. The observation of such anomalous temperature variation suggests to the Non-Fermi-liquid (NFL) behavior due to the presence of disordered 4f spins due to Ce-site dilution. Under the application of magnetic field, it is noted that a crossover from the NFL to a magnetic state occurs around 2 Tesla, where, short-range correlations among the spins is prevalent due to the dominance of coupling between the magnetic moments via conduction electrons. Magnetoresistance scaling indicates that behavior of disorder driven NFL state is described by the dynamical mean field theory of the spin glass quantum critical point.Introduction: -In the area of research on 4f electron based compounds, a challenge which remains elusive is to understand the physical properties of materials where singular interaction is mediated by soft collective modes. This investigation is important as the obtained results violate the applicability of Fermi-liquid (FL) theory [1-2]. The FL theory forms a basis to understand the electronic properties and according to this theory, electrical resistivity (ρ) varies as the square of temperature (T) and the ratio of heat capacity (C) and temperature i.e. C/T is constant [3][4].However, it has been noted in many 4f electron based compounds that the FL theory breaks down and shows a Non-Fermi-Liquid (NFL) behavior near quantum critical point (QCP). The ρ of such compound shows a linear behavior with T while, T variation of C/T is logarithmic [5][6][7][8].The observation of such NFL behavior might arise due to the presence of soft order parameter fluctuations resulting in singular interactions mediated between electrons [9][10][11]. In some
We report the magnetic, thermodynamic, and transport properties of a heavy fermion compound CeNiGe 2 . This compound undergoes two antiferromagnetic transitions around 4.1 and 3 K. It is observed in heat capacity that as magnetic field is increased to ~ 1 T, the two peak merge into a single peak around 3 K. However this peak is not suppressed under the application of magnetic field. Instead a new feature develops at 3.6 K above 1 T. The magnetic field induced new feature is investigated through entropy evolution, magnetic Gruneisen parameter and resistivity studies. These studies emphasis the fact that partial magnetic frustration due to field induced spin fluctuation is responsible for this observed feature. This partially frustrated regime develops a new antiferromagnetically ordered phase at high fields. In this compound magnetic field induced QCP is absent implying that the behavior of CeNiGe 2 is not in accordance to Doniach model proposed for heavy fermions compounds.
Studies connected with the investigations of "non-Fermi liquid" (NFL) systems continue to attract interest in condensed matter physics community. Understanding the anomalous physical properties exhibited by such systems and its related electronic structures is one of the central research topics in this area. In this context, Ce-based and Ce-site diluted (with nonmagnetic ions) compounds provide a fertile playground. Here, we present a detailed study of non-linear DC susceptibility and combined density functional theory plus dynamical mean field theory (DFT+DMFT) on Ce 0.24 La 0.76 Ge. Theoretical investigation of 4f partial density of states, local susceptibility and self-energy demonstrates the presence of NFL behavior which is associated with fluctuating local moments. Non-linear DC susceptibility studies on this compound reveal that the transition from NFL state to the new phase is due to development of the bi-quadratic exchange coupling and it obeys the non-linear susceptibility scaling. Under the application of magnetic fields, local moments interact spatially through conduction electrons resulting in magnetic fluctuations. Our studies point to the fact that the origin of the observed bi-quadratic exchange coupling is due to the spatial magnetic fluctuations.
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.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.