Irradiation driven magnetism enhancement in Y-doped HfO2 films

Abstract

HfO2-based ferroelectric films are regarded as core materials for next-generation nonvolatile memories and spintronics owing to their CMOS compatibility and exceptional ferroelectricity. Yet, the minute energy differences between polymorphs and the intricate defect–structure coupling have impeded precise, quantitative control of their ferroelectric and magnetic properties. Here, we introduce a non-equilibrium γ-ray irradiation strategy to modulate the magnetic response of 7% Y-doped epitaxial HfO2 thin films. Correlated structural, spectroscopic, and magnetic analyses reveal a nonlinear correlation between oxygen vacancies and lattice distortions. At an intermediate dose of 260 Gy, cooperative compressive strain and engineered vacancies boost out-of-plane saturation magnetization by 480%. Conversely, at 4800 Gy, excessive defect accumulation drives structural degradation and suppresses magnetism. X-ray diffraction, x-ray photoelectron spectroscopy, and scanning transmission electron microscopy jointly track the evolution of defect and lattice structure, elucidating a dose-dependent crossover from defect-driven magnetism enhancement to quenching governed by competitive defect–structure interactions. The work establishes a dose-defect-magnetism framework and provides a route toward magneto-electric cooperative control of wide-bandgap oxides for spintronic applications.