2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/228820We analyze the interference between tunneling paths that occurs for a spin system with both fourth-order and second-order transverse anisotropy. Using an instanton approach, we find that as the strength of the second-order transverse anisotropy is increased, the tunnel splitting is modulated, with zeros occurring periodically. This effect results from the interference of four tunneling paths connecting easy-axis spin orientations and occurs in the absence of any magnetic field.6 pages, 5 eps figures. Version published in EPL. Expanded from v1: Appendix added, references added, 1 figure added, others modified cosmeticallyMesoscale and Nanoscale PhysicsMaterials ScienceStrongly Correlated Electronstext