Observation of S=1/2 quasi-1D magnetic and magneto-dielectric behavior in a cubic SrCuTe2O6

We investigate the magnetic, thermal, and dielectric properties of SrCuTe2O6, which is isostructural to PbCuTe2O6, a recently found, Cu-based 3D frustrated magnet with a cornersharing triangular spin network having dominant first and second nearest neighbor (nn) couplings (Koteswararao et al 2014 Phys. Rev. B 90 035141). Although SrCuTe2O6 has a structurally similar spin network, the magnetic data exhibit the characteristic features of a typical quasi-1D magnet, which mainly resulted from the magnetically dominant third nn coupling, uniform chains. The magnetic properties of this system are studied via magnetization (M), heat capacity (C-p), dielectric constant (epsilon'), and measurements along with ab initio band structure calculations. The magnetic susceptibility chi(T) data show a broad maximum at 32 K and the system orders at low temperatures T-N1 approximate to 5.5 K and T-N2 approximate to 4.5 K, respectively. The analysis of the chi(T) data gives an intra-chain coupling, J(3)/k(B), to be about approximate to -42 K with non-negligible frustrated inter-chain couplings (J(1)/k(B) and J(2)/k(B)). The hopping parameters obtained from the LDA band structure calculations also suggest the presence of coupled uniform chains. The observation of simultaneous anomalies in epsilon'(T) at T-N1 and T-N2 suggests the presence of a magneto-dielectric effect in SrCuTe2O6. A magnetic phase diagram is also built based on the M, C-p, and epsilon' results.