Stimulated modulations in triplet spin coherent transients

Abstract
Modulations in coherent transients of photoexcited triplet electron spins in MgO are observed upon the application of a small magnetic field (H≲15G). The results are representative of a magnetic field stimulated dipolar interaction between triplet electron spins and fluctuating I = 5/2 nuclear spins of the 10% abundant 25Mg isotope. Using a memory‐function approach, it is shown that the modulation in the spin–echo amplitude decay arises in the limit of ’’slow exchange’’ among hyperfine transitions.