A Polling–Visualization–Reflection Approach to Teaching the Hanle Effect
Abstract
The Hanle effect is a foundational experimental method in spintronics, yet its conceptual interpretation often presents persistent challenges in advanced physics instruction. Although students can reproduce the Lorentzian dependence of spin polarization on transverse magnetic field strength, many struggle to connect this mathematical form to the underlying physical mechanisms of Larmor precession, phase dispersion, and ensemble dephasing. This disconnect between formal representation and causal reasoning limits coherent understanding of spin dynamics in upper-level undergraduate and graduate courses on magnetic semiconductors. This study introduces a structured Polling–Visualization–Reflection (PVR) instructional cycle designed to support conceptual restructuring of the Hanle effect. The approach integrates anonymous prediction-based polling, guided visualization of spin precession in a transverse magnetic field, and structured reflective articulation within a single lesson sequence. Implemented in an 80-min advanced spintronics session, the model explicitly targets representational translation between time-domain spin dynamics and field-domain depolarization curves. Classroom implementation results indicate clearer differentiation between spin relaxation and dephasing mechanisms, improved interpretation of Hanle curve width in relation to spin lifetime, and consistently high levels of student engagement. The instructional design requires minimal technological infrastructure and is adaptable to upper-level undergraduate and graduate physics contexts. These findings suggest that carefully structured interactive cycles can enhance conceptual coherence in abstract physics topics and provide a transferable instructional framework for aligning contemporary spintronics research concepts with classroom practice.