In this work,we have studied the structure and physical properties of a series of intermetallic compounds with the general formula CePd_(x)Ge_(2−x)(where,x=0.21,0.32,0.69).It was found that the compound crystallizes i...In this work,we have studied the structure and physical properties of a series of intermetallic compounds with the general formula CePd_(x)Ge_(2−x)(where,x=0.21,0.32,0.69).It was found that the compound crystallizes in three different phases with stoichiometries:CePd_(0.32)Ge_(1.68),CePd_(0.21)Ge_(1.79) and CePd_(0.69)Ge_(1.31) by varying the Pd to Ge ratio.While CePd_(0.32)Ge_(1.68) and CePd_(0.69)Ge_(1.31) crystallize in the hexagonal AlB2 structure type with the space group P6/mmm,CePd_(0.21)Ge_(1.79) crystallizes in the tetragonalα-ThSi_(2) structure type with the space group I41/amd.CePd_(0.69)Ge_(1.31) is in fact an ordered superstructure of CePd_(0.32)Ge_(1.68) with tripling of the c-lattice.Relative changes in the Pd/Ge ratio also impart substantial variation in their magnetic properties,although Ce is in the trivalent state in both the phases.CePd_(0.21)Ge_(1.79) shows metamagnetic behavior below 10 K whereas CePd_(0.69)Ge_(1.31) showed ferromagnetic behavior in the same temperature range.In addition to the metamagnetic behavior,CePd_(0.21)Ge_(1.79) also shows spin glass behavior at low temperature.DFT calculations were used to obtain ulterior information on the CePd_(0.69)Ge_(1.31) phase.Self-consistent calculations revealed that the ferromagnetic ordering of the ground state arises from the spins at the Ce and Pd sites.The observed sharp rise in the low temperature resistivity of CePd_(0.69)Ge_(1.31) is an indication of a pseudo-gap formation or possible Kondo behavior in the electronic density of states,enhancing the scattering of the charge carriers.Heat capacity measurements on CePd_(0.69)Ge_(1.31) suggest that it falls in the category of medium heavy fermion compounds.展开更多
基金We thank the Jawaharlal Nehru Centre for Advanced Scientific Research,Sheikh Saqr Laboratory and Department of Science and Technology,India(DST),and the Council of Scientific and Industrial Research(CSIR)(01(2787)/14/EMR-II)for financial supportS.S thanks the CSIR for research fellowship,D.K.and P.H.thank the UGC-DAE CSR,Mumbai center for project fellowship(Project No.CRS-M-166)S.C.P thanks the DST for the Ramanujan fellowship(Grant SR/S2/RJN-24/2010).
文摘In this work,we have studied the structure and physical properties of a series of intermetallic compounds with the general formula CePd_(x)Ge_(2−x)(where,x=0.21,0.32,0.69).It was found that the compound crystallizes in three different phases with stoichiometries:CePd_(0.32)Ge_(1.68),CePd_(0.21)Ge_(1.79) and CePd_(0.69)Ge_(1.31) by varying the Pd to Ge ratio.While CePd_(0.32)Ge_(1.68) and CePd_(0.69)Ge_(1.31) crystallize in the hexagonal AlB2 structure type with the space group P6/mmm,CePd_(0.21)Ge_(1.79) crystallizes in the tetragonalα-ThSi_(2) structure type with the space group I41/amd.CePd_(0.69)Ge_(1.31) is in fact an ordered superstructure of CePd_(0.32)Ge_(1.68) with tripling of the c-lattice.Relative changes in the Pd/Ge ratio also impart substantial variation in their magnetic properties,although Ce is in the trivalent state in both the phases.CePd_(0.21)Ge_(1.79) shows metamagnetic behavior below 10 K whereas CePd_(0.69)Ge_(1.31) showed ferromagnetic behavior in the same temperature range.In addition to the metamagnetic behavior,CePd_(0.21)Ge_(1.79) also shows spin glass behavior at low temperature.DFT calculations were used to obtain ulterior information on the CePd_(0.69)Ge_(1.31) phase.Self-consistent calculations revealed that the ferromagnetic ordering of the ground state arises from the spins at the Ce and Pd sites.The observed sharp rise in the low temperature resistivity of CePd_(0.69)Ge_(1.31) is an indication of a pseudo-gap formation or possible Kondo behavior in the electronic density of states,enhancing the scattering of the charge carriers.Heat capacity measurements on CePd_(0.69)Ge_(1.31) suggest that it falls in the category of medium heavy fermion compounds.
