  The magnetic Hamiltonian of the Heisenberg quantum antiferromagnet
SrCuTe$_{2}$O$_{6}$ is studied by inelastic neutron scattering technique on
powder and single crystalline samples above and below the magnetic transition
temperatures at 8 K and 2 K. The high temperature spectra reveal a
characteristic diffuse scattering corresponding to a multi-spinon continuum
confirming the dominant quantum spin-chain behavior due to the third neighbour
interaction J$_{intra}$ = 4.22 meV (49 K). The low temperature spectra exhibits
sharper excitations at energies below 1.25 meV which can be explained by
considering a combination of weak antiferromagnetic first nearest neighbour
interchain coupling J$_1$ = 0.17 meV (1.9 K) and even weaker ferromagnetic
second nearest neighbour J$_2$ = -0.037 meV (-0.4 K) or a weak ferromagnetic
J$_2$ = -0.11 meV (-1.3 K) and antiferromagnetic J$_6$ = 0.16 meV (1.85 K)
giving rise to the long-range magnetic order and spin-wave excitations at low
energies. These results suggest that SrCuTe$_{2}$O$_{6}$ is a highly
one-dimensional Heisenberg system with three mutually perpendicular spin-chains
coupled by a weak ferromagnetic J$_2$ in addition to the antiferromagnetic
J$_1$ or J$_6$ presenting a contrasting scenario from the highly frustrated
hyper-hyperkagome lattice (equally strong antiferromagnetic J$_1$ and J$_2$)
found in the iso-structural PbCuTe$_{2}$O$_{6}$.
