Long-lived magnons throughout the Brillouin zone of the strong-leg spin ladder (C7H10N)2CuBr4

Inelastic neutron scattering is used to measure spin excitations in fully deuterated single-crystal samples of the strong-leg antiferromagnetic S = 1/2 spin ladder compound (C7D10N)(2)CuBr4. Sharp resolution-limited magnons are observed across the entire one-dimensional Brillouin zone. The results validate the previously proposed symmetric spin ladder model and provide a reliable estimate of the relevant exchange interactions.