Magnetization Process of Atacamite: A Case of Weakly Coupled S=1/2 Sawtooth Chains.

We present a combined experimental and theoretical study of the mineral atacamite Cu_{2}Cl(OH)_{3}. Density-functional theory yields a Hamiltonian describing anisotropic sawtooth chains with weak 3D connections. Experimentally, we fully characterize the antiferromagnetically ordered state.