Anisotropic magnetic, transport and thermodynamic properties of novel tetragonal Ce2RhGa12 compound

Structural and magnetic properties of antiferromagneticCe2IrGa12

“…However, the T N of Ce 2 IrGa 12 is much lower than both the aforementioned compounds, suggesting that the substition of different transition metals does not simply correspond to a chemical pressure effect, but may otherwise tune the system, such as by modifying the electronic structure or carrier density. On the other hand, the substitution of Ir with Rh does correspond to a positive chemical pressure, since the lattice volume of Ce 2 RhGa 12 is 573.1Å 3 , and T N is enhanced slightly [33,37], which is consistent with our measurements of Ce 2 IrGa 12 under pressure. Furthermore the γ obtained from the C/T data above T N is 212 mJ/mol-Ce K 2 in Ce 2 RhGa 12 [33], which is larger than the value of 144.4 mJ/mol-Ce K 2 we obtain for Ce 2 IrGa 12 .…”

“…On the other hand, the substitution of Ir with Rh does correspond to a positive chemical pressure, since the lattice volume of Ce 2 RhGa 12 is 573.1Å 3 , and T N is enhanced slightly [33,37], which is consistent with our measurements of Ce 2 IrGa 12 under pressure. Furthermore the γ obtained from the C/T data above T N is 212 mJ/mol-Ce K 2 in Ce 2 RhGa 12 [33], which is larger than the value of 144.4 mJ/mol-Ce K 2 we obtain for Ce 2 IrGa 12 .…”

“…The specific heat of La 2 IrGa 12 below 5 K was fitted using C/T =γ+βT 2 , giving rise to a Sommerfeld coefficient γ=16.6(6) mJ/mol K 2 and β=2.84(4) mJ/mol K 4 . A Debye temperature of θ D =217.4 K was calculated using θ D = 3 12π 4 nR/5β, where n=15 is the number of atoms per formula unit, and R=8.314J/mol K. The same expression was fitted to the data of Ce 2 IrGa 12 in the paramagnetic state between 10 and 20 K, giving rise to γ= 144.4 mJ/mol-Ce K 2 , β=2.86(8) mJ/mol K 4 , and θ D =216.8 K. A similarly large γ of 140 mJ/mol-Ce K 2 was reported for Ce 2 PdGa 12 obtained from data at T >T N[30], while larger values of 191 mJ/mol-Ce K 2 and 212 mJ/mol-Ce K 2 were found for Ce 2 NiGa 12 , and Ce 2 RhGa 12[32,33]. However we note that an enhanced γ deduced from data above T N does not necessarily indicate heavy fermion behavior with large effective carrier masses, but may arise due to the presence of magnetic correlations above T N .…”

“…The T N values of Ce 2 M Ga 12 for M =Pd, Ni, Rh and Ir are 11 K, 10 K, 3.5 K and 3.1 K, respectively [30,32,33]. The unit cell volume of Ce 2 IrGa 12 (576.16Å 3 ) is slightly larger than that of Ce 2 NiGa 12 (564.9Å 3 ), while it is much smaller than that of Ce 2 PdGa 12 (579.64Å 3 ) [30,32].…”

“…Ce 2 PdGa 12 is a strongly anisotropic antiferromagnet with T N =11 K, where a ferromagnetic in-plane component appears below a second transition at 5 K [30,31]. Ce 2 NiGa 12 and Ce 2 RhGa 12 are reported to order antiferromagnetically at 10 and 3.5 K, respectively [32,33], while Ce 2 PtGa 12 exhibits two antiferromagnetic transitions at T N 1 =7.3 K and T N 2 =5.5 K [34]. Upon applying pressure, T N of Ce 2 PdGa 12 is suppressed, giving rise to a non-magnetic state at a critical pressure of around P c ∼7 GPa [35].…”