  We study the influence of ripple waves originating from the electromechanical
effects on spin relaxation caused by electromagnetic fields in armchair and
zigzag graphene nanoribbons (GNRs). By utilizing analytical expressions
supported by numerical simulations, we show that it is possible to tune the
spin flip behaviors ON and OFF due to ripple waves in GNRs for potential
applications in straintronic devices. This finding is similar to recently made
observations on the design of spintronic devices in III-V semiconductor quantum
dots, where the sign change in the effective Land$\mathrm{\acute{e}}$
$g$-factor can be engineered with the application of gate controlled electric
fields. In particular, we show that the tuning of spin extends to larger widths
for the armchair GNRs than for the zigzag GNRs. Here we also report that the
relaxation rate vanishes like $L^5$.
