1. Udumula Subbarao, Sebastian C. Peter*
Structure and Physical Properties of RE2AgGe3 (RE = Ce, Pr, Nd) compounds
Dundappa Mumbaraddi1, Sumanta Sarkar1, Pramod Halappa1, Sudhindra Rayaprol2, Sebastian C. Peter1*
Conclusion
Structure-property relations in the mixed valent rare earth based compounds crystallizing in the CeMn4Al8 type structure
Udumula Subbarao, Sebastian C. Peter*
New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, , India
Introduction
1New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research,
Jakkur, Bangalore , India.
2UGC-DAE Consortium for Scientific Research, R-5 Shed, B.A.R.C Campus,
Trombay, Mumbai , India
The polycrystalline samples of RE2AgGe3 (RE = Ce, Pr, Nd) were prepared by arc-melting process. Phase identity and pristine were determined by powder X-ray diffraction (PXRD) and samples were characterized by single crystal XRD .
Structural Diversity of RE2TX3
Synthesis
Er2RhSi3
P63/mmc
The globules were flipped several times and remelted
The elements were loaded into water cooled copper hearth conditions
2a, 2b, c
Ce2NiGe3
P6/2c
U2RuSi3
P6/mmm
Melted under Ar atmosphere
a, b, 2c
Motivation
AlB2
(P6/mmm)
a, b, c
Rare earth intermetallic compounds show various physical properties such as structural phase transition, giant magneto resistance, superconductivity, magnetic ordering, spin glass behavior, magneto-caloric effect and valence fluctuation.
RE2AgGe3 showed ordered superstructure in the AlB2 type family and temperature dependent structural phase transformation.1,2,3,4,5
2a, 2b, 3c
a, b, 3c
Ce2PdGe3
P6/mmm
Eu2AuGe3
Fmmm
2a, 3b, 4c
Cooled down to room
temperature slowly
Globules crushed and annealed at 800oC for 2 days
Arc- melter
Eu2AgGe3
Fddd
Characterization
Crystal Structure of RE2AgGe3
Resistivity of Ce2AgGe3
α-ThSi2 ,I41/amd ,Tetragonal.
Ce2AgGe3
Compound
a (Å)
c (Å)
V (Å3)
Ce2AgGe3
4.275
14.685
268.4
Pr2AgGe3
4.240
14.611
262.7
Nd2AgGe3
4.189
14.557
255.4
Magnetism of Ce2AgGe3 and Pr2AgGe3
Ce2AgGe3
Ce2AgGe3
Pr2AgGe3
Future Direction
References
(i) A series of new intermetallic phases with disordered superstructure in α-ThSi2 type family have been synthesized by arc melting method. (ii) Magnetic measurement on Ce and Pr compounds reveal that the former couples ferromagnetically whereas the latter undergoes a spin glass transition at low temperature. (iii) The resistivity measurements on Ce2AgGe3 shows metal like behavior at low temperature with a Fermi liquid ground state and a magnetic transition below 6.4 K.
We are planning to perform neutron scattering measurements on all the samples to know magnetic structure.
Magnetic measurement on Pr2AgGe3 hinted towards spin glass state has to be confirmed by AC susceptibility.
Sarkar, S.; Peter, S. C. Inorg. Chem. 2013, 52, 9741−9748.
Peter, S. C.; Malliakas, C. D.; Chondroudi, M.; Schellenberg, I.; Rayaprol, S.; Hoffmann, R-D Pӧttgen, R.; Kanatzidis, M.G. Inorg. Chem. 2010, 49, 9574–9580.
Sarkar, S.; Peter, S. C.; Kanatzidis, M.G. Inorg. Chem. 2012, 51, 10793−10799.
Sarkar, S; Peter, S. C. J. Chem. Sci. 2012, 124,
Sengupta, K.; Sampathkumaran, E. V.; Nakano, T.; Hedo, M.; Abliz, M.; Fujiwara, N.; Uwatoko, Y.; Rayaprol, S.; Shigetoh, K.; Takabatake, T.; Doert, Th.; Jemetio, J. P. F. Phys. Rev. B 2004, 70,
We thank JNCASR, Sheikh Saqr laboratory and DST for financial support. DBM thanks UGC-DAE CSR for the project fellowship. S. S. thanks the CSIR for research fellowship. SCP thanks DST for the Ramanujan fellowship.
Acknowledgement
Thank You…