Experimental verification of inverse orbital Hall effect using CoFeB/Cr/heavy metal structures

Abstract

Spin current, the flow of spin angular momentum, is fundamental to spintronics and spin-based energy conversion. However, its limited propagation length and low generation efficiency hinder further technological progress. As an alternative, orbital current—arising from electron orbital angular momentum—shows considerable promise, especially in metals with large orbital Hall conductivity. Moreover, orbital current in light metals can travel farther than spin current, underscoring its potential for next-generation spin-orbitronic devices. Despite these prospects, direct experimental verification of orbital currents has remained elusive. Here, we report the electrical detection of orbital-charge conversion, known as the inverse orbital Hall effect (IOHE), by performing dynamical spin injection experiments on CoFeB/Cr/(Pt, Ta, W) multilayer structures. Our results provide a direct observation of IOHE, paving the way for advanced spin-orbitronic applications.